A REVIEW OF THE LANCELETS, HAG-FISHES, AND LAM-rREYS OF JAPAN. WITH A DESCRIPTION OF TWO NEWSPECIES.
By David Starr Jordan and John Otterbein Snyder,Of the Ldand Stanford Junior IhiversUy.
In the present paper is given an account of the Lejjtocardii and Mav-slpohranchii^ lancelets, hag-fishes, and lampreys, known to inhabitthe waters of Japan. It is based on material collected liy the writersin Japan, in the summer of 1900, under the auspices of the HopkinsLaboratory of Stanford University. Series of the species named aredeposited in the U. f^. National Museum.Class LEPTOCARDII.THE LANCELETS.Skeleton membrano-cartilaginous. Notochord persistent and ex-tending to the anterior end of the head, inclosed in a membranoussheath as is the cord-like nervous axis above it. Heart a longitudinaltubular vessel which gives off branchial vessels which unite in an aorta;end of the nervous axis not dilated into a brain and not surrounded bya protective capsule, or skull. Blood colorless. Respiratory cavityconfluent with the cavity of the abdomen; gill slits in great number,the water being expelled through an abdominal pore in front of thevent. Jaws none; the mouth a longitudinal fissure, with cirri on eachside. Body lanceolate in form, more or less fish-like, and not envel-oped in a tunic. Dorsal fin present, low: anal fin usually more or lessdeveloped.Small marine animals, highly interesting to the zoologist as exhibit-ing the lowest degree of development of the vertebrate type. Theclass includes but the single order, Ainphio.fi or Cirrostoini. (XerrTog,thin: Kapdia, heart.)Proceedings U.S. National Museum, Vol. XXIII?No. 1233. 725
7t>6 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxih.Order AMPHIOXI.THE CIRROSTOMES.This order is equivalent to the family Branchlostom khe. {ai.i<J)i. l)oth
;
oBv5. sharp: Cirrostomi is from c/'rrus, a look of hair; ffro/ia^ mouth.)Family I. BRANCHIOSTOMID.E.THE LANCELETS.Body elongate, lanceolate, compressed, naked, colorless; the tins rep-resented I)}' a low fold extending along the back, with usually a rudi-mentary fold l)elow which passes by the vent to the a)>dominal pore.Mouth inferior, appearing as a longitudinal lissure, surrounded byconspicuous, rather stiti', cirri. Eye rudimentary. Liv^er reduced toa blind sac of the simple intestine. Small, translucent creatures foundembedded in the sand on warm coasts throughout the world. Thespecies are all very similar in appearance and hal)its, and the numbersof the muscular impressions furnish the only characters thus far knownby which the species can be distinguished.
?. Gonads (reproductive structures) present on both sides of the median hue; anal tinpresent with traces of tin rays; no caudal process Brancjiiostoma, 1
1. BRANCHIOSTOMA Costa.BnuicJiiostojmtCosTA, Cenni ZoologiciXapol., 1834, p. 49 (liunbricinn^koiceulatinii ).Amphioxus Yakrell, British Fishes, 1836, p. 468 {lanceolatus).Lancelots with the gonads or reproductive structure present on bothsides of the median line. Anal tin present, with traces of rays. Ver-tebral column not produced backward into a caudal process. Six orseven species recognized, found in the warm seas, usuallv buried insand flats at no great depth. The}' are very tenacious of life, and willendure considerable mutilation. (/tfprt';KJ^^, gills: ffro/na. mouth?thecirri about the mouth having been taken for gills b}' Costa.)
o. Myocommata or muscular bands, 62 to 64.h. Myocommata behind vent, 10 or 11, the formula usually 37 ? 16 4-11 =64 Xakaoaw.k, 1
I. BRANCHIOSTOMA NAKAGAWiE Jordan & Snyder, new species.AmphioxuK sp. Andrews, Zool. Anzeiger, 1895, p. 468, Goshi-no-ura, Amakusa,Buzen.Amp}iio.rui< sp. Nakagawa, Annot. Zool. Jap,, I, 1897, \>. 127. Goshi-nu-iira inHigo, Shikajima in Chikuzen.Muscular bands, 37 + 10 + 11 = 64. Usual length, 1 to 2 inches.Bod}^ relatively long, the tail short, the form rather stout. Sandycoasts of Japan, from Misaki southward to Kiusiu, our specimens fromMisaki, presented by Dr. Mitsukuri. Others in Imperial Universitycollected at Bungo by Dr. S. Matsubara, at Shikajima, by Dr. S. Hatta,
N0.1J33. LAXCELETS, etc. FliOM JAPAX-JOEDAX AXD SXYDEn. 727and at Misaki (Koajiro Bay) by Dr. H. Nakag-awa. Dr. Ethan A.Andrews further records specimens from Goshinoura. Amakusa, andBuzen. in Kiusiu. Dr. Andrews, on specimens from Kiusiu, countsthe nuiscular bands as 37 + 16 + 11 = 64. On the type specimen fromMisaki. very carefully counted for us, by Dr. Nakagawa. in theImperial University, the following numbers were found in a specimenof -15.5 M. Right side, 37+ 16^ 10 = 63.Left side, 37 + 16 -i- 1 1 = 64.The specimens from near Misaki were taken in Koajiro Bay. justnorth of Misaki. ))y the veteran collector, Kumakichi Aoki, of Misaki,The Japanese lancelet is very closely allied to Branchiostotna hel-chiv'i (Gray), {Aiiq>h(o,L'm hdcherl Gray),' from Bass Straits. Accord-ing to Dr. Giinther, the types of this species have the muscular bands37 -|- 14 -|_ 13^ the tail longer and the body shorter than in the Japaneseform. It is possible that this ditierence is due simply to errors incounting. In view, however, of the almost entire difference in speciesin the shore fauna of Japtm and that of Borneo, it seems to us best toregard the Japanese lancelet as a species distinct from B. helcherl.It needs comparison with no other.Named for Dr. H. Nakagawa. of Tokyo, well known as an entoinol-oo-ist, in recoo-nition of his excellent work on the present species.Class MARSIPOBRANCHII.THE MYZONTS.Skeleton cartilaginous; the skull imperfectly developed, not sepa-rate from the vertebral cohunn. No true jaw^s, no limbs, no shouldergirdle, no pelvic elements, no ribs. Gills in the form of lixed sacs,without branchial arches, six or more in number on each side. Nos-tril single, median. ^Nlouth subinferior, suctorial, more or less circu-lar. Heart without arterial bulb. Alimentary canal straight, simple,without ct^cal appendages, pancreas, or spleen. Generative outletperitoneal. Vertical iins with feeble rays, usually continuous aroundthe tail. Naked, eel-shaped animals. inha))iting cool waters, both freshand salt. They undergo a metamorphosis, the young being oftenquite unlike the adult. {itapffiTriov. pouch; 0pdyxi(^. gills.)OKDERS OF MARyiPOBRANCHII.
a. Nasal tube duct-like, with cartilaginous rings penetrating the palate; gill ()i)en-ings remote from the head, opening directly into the pharynx; no eyes.Hyperolrdiaa. Nasal duct a blind sac, not penetrating the palate; gill openings close behind thehead, conuuunicating with a conunon branchial passage which opens directlyinto the pharynx; eyes well developed in the adult Hyperoartu
^ Proc. Zool. Soc. London, 1847, p. 35.
728 PROCEEDINGS OF THE XATIOXAL MUSEUM. vol.xxiii.Order HYPEROTRETI.THE HA(iFISHES.No.stril tube-like, with eartilag-inous rings, penetrating the ])alate,its position at the extremity of the head, over the mouth; snout witheight har})els; mouth without lips; one median tooth on the palate andtwo comlj-like series of teeth on the tongue. Brantdiial apertures ata great distance from the head; a series of mucous sacs along eachside of the abdomen. Intestine without spiral valve. Eggs large, witha horny case provided with threads for adhesion. Marine lamprey-like animals, burrowing into the flesh of fishes, on which they feed.They may be referred to two families, ditfering mainly in the struc-ture of the gill openings, {imspcoa. palate; Tpi/rns, perforate.)
n. P>ranchial apertures six to fourteen on eaeh side, eaeh leailintr ))y a duet to abraneliial sae Eptnlntklxan. Braneliial apertures single on each side, from which diverge duets to six bran-(!hial sacs yrii.rinidxFamily II. EPTATRETID.E. ^This family differs from the 2[i/.rl)il<J(e chiefly in the structui-e ofthe ))ranchial apparatus, there ])eing six to fourteen sacs on each sidewhich receive Avater directly from the esophagus, as in My.ilne^ butthe emptying ducts, instead of passing backward and downAvard to acommon external opening, as in Mi/.rhie, pass directly through theAvail of the body, so that there are as many external openings as thereare gill sacs. Species few, inhabiting the colder parts of the Pacific,their habits similar to those of My.rl)}e <jh(trno.'?i.The hagfish fastens itself usually on the gills or isthnuis of largefishes, sometimes on the eyes, whence it works its AAay Aery rapidlyinto the inside of the body. It then devours all the llesh of the l)odyAvithout breaking the skin, so that the fish is left a living hulk ofhead, skin, and bones. It is especially destructive to fishes taken ingill nets. In gill nets, in summer, these empty shells of fishes arcoften obtained. When these are taken from the AAater. the hagfishscrambles out Avith great alacrity. It is thought that the hags enterthe fishes after they are caught. A fish of 1(? to 1.5 pounds weightAvill l)e devoured bA' them in a single night.
(t. Gill openings six to eight on each side Eptalretu.s, 2
' We adopt the name Eptatretns instead of Homea in deference to the argument ofProfessor (iill in the following ])aper.
I
Ko.12.3. LAXCELETS, etc., FROM JAPAN-JOIWAX AXD SXYDER. 729
2. EPTATRETUS Dunneril.
Epiatren.s (Dumeril) CunnKT, Dirt. Sri. Nat. XV. ISU), p. 134 {<h>v,beii Dumeril,not Lac^pede).Homea Fleming, Philos. Zool., II, 1822, p. 374 {banks,).Les Heptat^'h.rs Doieril, Cuvier Regne Anim., 2d ed., II, 1829, p. 405 iarrhatm)Heptatreme. (Dumeril) M'MrRTRiE, Anim. Kingdom, II, 1831, p. 29S {nrrhatm).Heptatrema XoiOT, Das Thierreich, II, 1832, p. 529 {cirrhatus).Bdeimoma MI^ller, Abb. Ak. Wiss., Berlin, 1834 {he.rairema)Hrptafrem,'.^GmFFvm, Animal Kingdom, X, 1834, p. 621 (orrhatu.).This o-enus includes those E}>tatret>d<x which hare six to eight gillopening" , thus differing from the West American genus. Polutotrema,which has from ten to twelve.
2. EPTATRETUS BURGERI (Girard).NUTAUNAGI OK SLIME-EEL.(Plate XXX.)Heptmiema cirrhatum Schlegel, Fauna Japonica, Poiss., 1847, p. 310, pL cxliii,Na-a^aki (not Petromyzon cirrhdus Forster, from Soutb Afru-a).BdelkJoma eirrhatian Ishikawa, Cat., 1897, p. 63, Coast of Musasbi (off Tokyo .B.Mloston>a hurgM Girard, Proc. Ac. Nat. Sei. Phil., 1854, p. 199, after Scldegel.Snout 6 to 6f in distance to first gill opening; gill area, with sixopeninos, somewhat longer than snout; last gill opening on the leftside do'uble the size of the others; eye well developed; head, to gillopening, 3^ to 3| in length of body: barbels, eight, the outer buccalb'lrbels^lono-est 2 to 2| in snout: inner short and thick; nasal 1)arbelslono- much'longer than la])rum, the lower longest; teeth in upper rowabout 11 in number; tip of snout or labrum very broadly rounded:its width oreater than length of upper barbel; dorsal and anal hnsspreadino-'widelv on the tail; greatest breadth of tail with hns oneand one-half times length of snout; tail, from vent. 2i in head, fromgill opening. , . , i ^Color purplish or plum color, the belly a little dorsal, and analdarker, conspieuouslv edged with pale; a pale ridge about middle lineof Lack: l>arbels pale; row of slime pores distinct along whole lengthof l)odv. ^^ , ., JCoasts of Japa.i, from Tokvo southward, not rare. Here describedfrom three large examples, the largest ISi inches long, from SagamiBav (off Misaki and off Enoshima). and from one about a foot inleiio-th from Wakanoura. In all these the number of gill openings issix'^on each side. The specimen from Waktuioura has the snout verymuch shorter than either of the others, the outer buccal barbelreaching within half its length of the eye, almost a whole length shortin the oUiers. No other important differences appear, and probablythi. i^ within the range of individual variation. It is barely probable
730 PBOCEEDINGS OF THE NATIONAL MUSEUM.that the specimen from AVukunom-u. with the short snout, may belongto :i distinct species. In ueneral, the example tioinvd ])v us (from offEnoshima: Collection of U. S. Fish Connnission steanier A//n/fro.s.s)aorees with Schleg-eFs plate.With the species of Myxhu, this species is known to the Japanesefisherman as jShdaunagi or slime-eel. The two species are alike insize, color, and hal)it. Eptatretus hurgeri may he known hy the pres-ence of six gill openings on each side, instead of one. l)v tluMery bluntupper lip or tip of snout, and by the paler edges to the tins. The eyeis much more distinct than in Jfyxine.
^ Named for its discoverer. Burger, who collected for Siebold andSchlegel. Family III. MYXINID^F].Body eel-shaped, covered hy a thin skin, which is easily detached.Along the lower side, for nearly the. whole length of the animal, arctwo rows of mucous glands, each with an external opening, yieldingan al)undance of nuicus, which renders these animals excessively slimy!No eyes. Brain small, of the normal tish type. Skull little devel-oped, cartilaginous: the flexible notochord inclosed in its sheath andextending from the base of the skull to the end of the tail, represent-ing the spinal cohunn. ^k)uth round, suctorial, without lips, with afew barbels on each side. Nostril single, large, on the median lineabove, and at the very front of the head, provided with two pairs ofbarbels. Teeth strong, a single median one on the roof of the mouth,and two rows on each side of the tongue, which is a powerful organ,'with a strong, tiln-ous tendon moving in a muscular sheath. Alimen-tary canal a simple, nearly straight tube, without spiral valve; gillsacs placed on each side of the (esophagus, lying directly against ^'itsouter walls. The water passes into them hy a small pore openingdirectly from the (esophagus into each sac. It is then passed out ])y aduct, which continues backward along the outer walls of the sacs tothe abdominal wall at the end of the last sac, where all the ducts fromone side unite into one. and the water is emptied at the branchial open-mg on each side of the median line. In close comiection with thebranchial opening on the left side there is a third opening that leadsby a very short duct to the (esophagus, and hence into the branchialsacs, at the times when the supply of watei- is cut off by the head ])eingburied in the flesh of the animal on which it feeds. Vent close to tipof tail. Ovary single, on the right side. No oviducts; the matureeggs falling into the abdominal cavity and excluded through the peri-toneal opening at the side of the vent. Eggs with a horny case, andthreads for adhesion. Parasitic anhnals, burrowing into the })odies offishes, and found in the cold seas. One genus, with several species,found in most cold seas.
NO. 1233. LANCELETS, ETC., FROM JAPAN?JORDAN AND SNYDER. 731
3. MYXINE Linnaeus.
3/y.f('Hf LixN.Eis^, Systenia Naturjv, 10th ed., 175S, p. (i5() ((jUdinmd).Ga-strobranchus Bloch, lohth., XII, 1797, p. 51, pi. c-t'ccxiii {arcuti).Murxnoblenna Lacepede, Hist. Nat. Poiss., V, 1803, p. 647 {nlinacea).Anopsus Rafinesque, Anal, de la Nature, 1815, p. 493 (ollracca).Characters of the genus included above.(An old name, from fivca, slime.)
3. MYXINE GARMANI Jordan and Snyder, new species.Mijxbie inhstralis GtiXTiiEH, Challenger Fishes, 1887, p. 2H7, not type, Hyalonema
"Ground off Enoshima.M(/xine sp. Garman, Deep Sea Fishes, 1900, p. 345.Teeth in upper series ten in number: the anterior three continentat base but not enlarg-ed, rather narrow and not longer than the nextteeth; labruni or tip of snout above narrowly triangular, pointed attip, resembling the })arl)els. and searc-ely shorter than the barbelstanding next; pectoral pores about thirty; nasal barbels well devel-oped, the upper somewhat shorter; buccal barbels prominent, theiiuier pair short and thick, the lower longer than the rostral l)arbels.Gill openings moderate, inserted a little before end of first third of body;vent a little before middle of dorsal tin; anal scarcely as deep as borsal.Color dark purplish l)rown or plum color, slightly paler below;barbels pale; dorsal and anal not edged with paler, no pale ridgealong back.Described from three specimens, the largest 19i inches long, in linecondition, the others injured, all taken oli' Misaki, where the speciesis rather connnon.It was first noticed by Dr. Giinther who had half a dozen specimensfrom the Hyalonema grounds oil' Enoshima. at a depth of 345 fathoms.Dr. Giintber identities these specimens with Myxme australis eTenyns,from Patagonia, and further ''believes" on rather scanty evidence
"that Ileptatreiiia drrhatnni of '^(^XAq^qX {Eptatretushurgeri) ^\\o\\\^be referred to the same species.''As to this Mr. Garman very properly observes: "The results ofcomparisons of representatives of the genus from other parts of theworld are such as to raise doubts concerning the specific identity ofthe Japanese species with either of the species of ^fyxinc from otherregions.''The Japanese form is in fact distinct, allied to M. trldentlger Gar-man, from Sandy Point, Patagonia, in its dentition, and to M. acuti-frons Garnian, from the same region, in the form of its labrum, orfront of snout.Named for Samuel Garman, of Harvard University, in recognitionof his excellent work on the species of Myxine.
732 PROCEEDINGS OF THE NATIONAL MUSEUM. v,,i xxm.Order HYPEROARTII.THE LA:\rPREYS.ISasal duct a l)liiul sac. not ])enetratinif the palate. This order isequivalent to the sing-le family J\ir<nnijz<>niiJ<v. {t)7Tepcoa\ palate:apring^ complete; i. e.. entire.)Fiimily IV. PETROMYZONID.E.(THE EA:\rPREYS.)Body eel-shaped, suhcylindrical anteriorly, compressed behind; themouth nearly circular, suctorial, usually armed with horny teeth,or tooth-like tul)ercles which are simple or multicuspid resting- onpapillii?; those immediately above and those immediately below theoesophagus more or less specialized; eyes developed in the adult: gillopenings 7. arranged in a row along the sides of the '* chest:" nostrilon top of the head just in front of the eyes; lips present, usuallyfringed; dorsal tin more or less deeply divided by a notch; theposterior part commonly continuous with the anal around the tail;intestines with a spiral valve; eggs small.These animals undergo a metamorphosis; the young are usuallytoothless and have the eyes rudimentary. Separate generic names{AmmoavtcK, ScolcC(ts(irn((^ CJillnptci'iix) had been applied to theselarval forms before it was discovered that they were the normal youngof the true lampreys.The lampreys inhabit rivers of temperate regions. They attachthemselves to fishes and feed ])y scraping oH' the ilesh with their rasp-like teeth. Most of them ascend rivers or brooks at the spawningseason, after which very many of the individuals die.
a. Second dors^al continuous witli caudal.
''. Snpraoral and infraoral lamin;v with teeth or tooth-hke tubercle;^.
r. Supraoral lamina very large, expanded laterally, fonning a crescent-Bhaped plate with a cusp at either end and rarely a very smallmedian cusp; anterior lingual tooth little developed, its edgecrescent-shaped and dentate, the middle denticle enlarged; buccaldisk sniall, the lateral teeth small and never tricuspid; dt?rsal finsseparate or united at ]>ase: small lam})reys; fiuviatile. Lampetni, 4.4. LAMPETRA Gray.Ldiiipefrii Gray, Proc. Zool. Sot-. London. LSol, p. 2oo [HufidUs).Lampreys of small size, with the dorsal hn emarginate. or dividedinto two parts, the posterior portion continuous with the low anal tinaroiuid the tail; supraoral lamina broad, forming a crescentic plate,with a large l)luntish cusp at each end. and rarely a very smallmedian cusp; lingual teeth small, with a crescent-shaped dentateedge, the median denticle enlaroed: buccal disk small, its teeth few
NO. 1-33. LANCELETS, etc., FROM JAPAN?JORDAN AND SNYDER. 733and never tvieuspid. SnuiU lampreys inlia))itino- the brooks of Europe,Asia, and North Ameriea.
a. Dorsal tin divided into two parts, separate or joined at l)ase only; intraorallamina with 6 to 8 sharp cusps joj^nwd, 4aa. Dorsal fin distinctly continuous, but with a sharp notch; infraoral lamina with6 to 7 blunt cusps mitsuknrli, 5
4. LAMPETRA JAPONICA i Von Martens).YATSLTMEUNAGI (EIGHT-EYED EEL).PetfoviyzonjaponicusMARTEyis, Archiv. Naturg.. XXXIV, 1868, p. 3; Japan.Pdwmyzon fuviatUis Ishikawa, Prel. Cat., 1897, p. 63, Yamagata, Xiigata,Takata, R. Shimigu, Totomi, Owari, Kioto, Uji in Yamashiro, Lake Biwa atXagahama in Omi, Hatta, Lampreys of Japan. Rivers of southern Hondo.(Xot of Linnfeus.
)
Siipraoral lamina formino- a long, crescentic plate, with a sharpcusp at either end; no median cusp; infraoral lamina with seven (sixto eioht) sharp cusps, which are nearly equal, except that the outer ismuch broader than the others; lateral teeth, three on each side, eachwith tw-o c-usps; tong-ue with nine cusps, the median nmch the larg-est; lips fringed; tw^o rows of simple teeth in front of mouth above.Dorsal tins entirely separate, the first not quite half the height of thesecond, the interspace '21 in head; 2i in length of first dorsal. Gillopeninus, 7; head, lyV in thorax; snout. If in head; head, lU in totallength; greatest depth, If in head. Tail, 4i in total length. Blackish;paler below; tail darker; dorsals edged with pale.Rivers of southern Hondo, north al)out to Niigata and 8endai, gen-erally common. Here described from a specimen 18i inches longfroni Shinano River in Echigo. Other specimens obtained by us arefrom near Tokio (infraoral cusps six. the outer more enlarged); onefrom Noyshiro. six cusps; Noyshiro. eight cusps, the two outer coal-escent on either side.This species is very close to Lanipetra aurcd (Bean), of the YukonRiver, and to Lmipetra jimkitilk Linnteus, of the streams of Europe.Our material is not sufficient to show that it is really different fromeither or both of these. It is, however, very undesirable to tmitenominal species from widely separated regions lintil identity is actu-ally shown. This species seems to have a higher second dorsal thanthe European species. From Dr. Hatta"s map of the distri])ution oflampreys in Japan, it is evident that the present species has a muchmore southerly range than the other. This would indicate that it isnot identical with the lamprey of the Yukon. The species is knownin Japan as Y'atsumeunagi, or Eight-eyed Eel.Lampvtra ermtii (Dybowski) (Fischfauna des Anmrgebietes, 187'2,2l>(?), from the mouth of the Amur, is also close to Lainpetra japun-iea, but is said to have 19 denticles in a row acros.s the tongue.
734 PROCEEDINOS OF THE NA TTONAL MUSEUM.
5. LAMPETRA MITSUKURII iHatta).Petromyzon hranchiaUs Ishikawa, Prel. Cat., 1897, p. 83, Sapporo, Hokkaido.Hatt.v, Lampreys of Japan, rivers of northern Japan (not of Linnwus).Lamiietra mUmhirii Hatta, Ms. ba.sed on Petromiizon hranchkdii< Ilatta, not ofLinnffu.*.Lmnpctra mitmkurii Jordax and Snyder, Proe. F. S. Xat. Mus.. 1900, p. o.'id ( hmdescription; young specimens from Tokio and Lake Biwa referred to liyerror; thoj^e belong to L.japoniea):?Jordan &. Snyder, Catal. Fisli .Taiiau1901.Supraoral lamina formino- a crescentic plate, shortei- tliau in Z.japomea, the cusp at either end shorter and more obtuse; infraorallamina with about six blunt cusps, the outer ones much broader andlonger than the others; lateral teeth three on each side, each bicuspidand blunt, two or three rows of simple teeth in front of supi-aorallamina: lips fringed.Dorsal tins connected, the tirst two-tifths to one-third height of sec-ond, the connecting membrane of the two tins a])out one-third heightof first. Head li in first dorsal, aliout one-tenth longer than thorax:gill openings, 7; head, 9 in total length; tail. 4: (>2 muscular impres-sions between gill openings and vent.Color bluish-black, the bell}- white: tip of tail l)lackish: tins pale.edged Avith darker.Rivers of Hokkaido, and Hondo north of Sendai and Niigata, gener-ally common. Here described from eight specimens, one 5i, theothers 12 to 14 inches in length, obtained from the Ishikari River, atSapporo in Hokkaido. The smallest one has seven infraoral cuspsand the teeth are less developed. It agrees in all other regards withthe largest one.From the lampreys of southern Japan this species is at once dis-tinguished by the united dorsals.This species is related to Lampetra wilderi of the eastern UnitedStates, and still more closely to Lampetra p)laneri (Bloch) of Europe.It will require actual comparison of specimens to separate it from thelatter, but our experience with other species in widely separated regionsshows that it is very hazardous to assume identity of species simply])ecause superficial and noncomparative descriptions indicate no differ-ence. The Japanese species seems to reach a larger size and to havehigher tins than the European.Named for Professor Mitsukuri, of the Imperial University of Japan.
U. S. NATIONAL. MUSEUM PROCEEDINGS, VOL. XXIII PL. XXX
The upper ilkistration represents an under view of the head of Myxme garmaiti,for description of which see page 731.
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