228 General Notes.
southern Texas, Louisiana and Florida is only from 17.11 to IS. 4 mm.
This larger animal is Dasypterus intermedins (II. Allen), originally de-
scribed from Matamoras, Tamaulipas. While it is not possible, in the
absence of a better series of skins than that now available, to find any
appreciable differences between the Yucatan and Chiapas specimens and
true intermedins, it is evident that the form occurring in Louisiana and
Florida ( D. floridanus Miller) is sufficiently characterized by its shorter
forearm and third ringer to be regarded as distinct.—Gerrit S. Miller, Jr.
THE VOLCANO RABBIT OF MOUNT IZTACCIHUATL.*
In the catalog of the objects exhibited by the Mexican "Comision
"
Geografico-Exploradora at the Columbian Exposition in Chicago t Pro-
fessor Augustin Diaz figures (pi. -L' ) a rabbit of the genus Romerolagus,
under the name " Conejo del Volcan (Lepus diazi Ferrari -Perez, sp.
nov)." This plate is not mentioned by Merriam in the original descrip-
tion of Romerolagus nelsonii from Mt. Popocatepetl, or by Nelson in his
monograph of the Rabbits of North America, § though it is alluded to by
an anonymous editorial writer in Natural Science for March, 1897. ||
The validity of the specific name diazi is unquestionable under the
Internationa] Code of Zoological Nomenclature (Art. 25, and Opinion 1).
According to the same Code the authority for the name is Diaz, not
Ferrari-Perez, since Lepus diazi remained in MS. until the publication of
the catalog by Diaz, and no statement is anywhere made that
" some
other person is responsible for [the publication of] said name and its indi-
cation [= illustration]" (Art. 21, and Opinion 4).
Nonienclatorily the case presents no difficulties, but zoologically it has
hitherto been obscured by the uncertainty as to whether the
" Volcano
Rabbit" was identical with Romerolagus nelsoni. This doubt has now
been removed by the kindness of Professor Ferrari-Perez, through which
I have been enabled to examine the type and a second specimen of
Romerolagus diazi. Both were taken in Puebla, on the eastern slope of
Mt. Iztaccilniatl, a region about fifteen miles from the type-locality of
Romerolagus nelsoni.
As compared with four skins of Romerolagus nelsoni the two specimens
of R. diazi (both marked female, the type taken in March, 1885) show
slightly less black in the grizzle of dorsal surface and slightly more gray
on cheeks, characters probably due to the fading usual in mounted spec-
* By permission of the Secretary of the Smithsonian Institution.
-rExposicion Internacional Columbina de Chicago en 1893 ComisiYm| Geografico-
Exploradora de la| I Reptiblica Mexicana | Catalogo de los| objectos que componen el
eontingente de la Comision, precidido de algunas notas sotare su| organization y
trabajos por el ingeniero director Agusttn Diaz Coronel deI EstadoI | Mayor Especial,
Ex-Profesor en el Colegio Militar y en la Escuela de| Especial Ingenieros I Xalapa-
Enriuuez. Marzodel893 I Tipografia de la Comisi6n Geografico-Explnntdora. |
t Proc. Biol. Soe. Washington, X, pp. 109-174. December 29, 1896.
§ North American Fauna No. 29. August 31, 1909.
II X, p. 151.
General Notes. 220
imens. The skull of the type (that of the other .specimen is missing)
lacks the mandible and the entire basal part of braincase, though the
remaining portion is in fair condition. It has certain peculiarities not
shared by any of the live skulls of R. nelsoni: the postorbital processes
are broader and heavier, the palate is more arched between toothrows,
and the dorsal profile of braincase is less bent downward posteriorly.
These cranial characters are, however, quite within the range of normal
variation in members of the family. I consequently have no hesitation
in regarding the later name nelsoni, as a synonym of diazi. Mr. E. W.
Nelson, who examined the specimens with me, is of the same opinion.*
Measurements of the type specimens (those of R. "nelsoni" in paren-
thesis): hind foot, 48.6 (53); ear from crown, 38.6 (37); greatest length
of skull, 60.4 (60.6); zygomatic breadth, 2!)+ (30.4); breadth of brain-
case, 22.6 (23.4) postorbital constriction, 10. (9.8); interorbital con-;
striction 9.8 (10.0); nasal, 24.4+ (24.8); greatest breadth of both nasals
together, 9.8 (10.0); diastema, 16.0 (15.8); length of palate (lateral),
7.4 (7.S); width of palate between anterior premolars, 8.0 (7.6) width;
of palate between posterior molars, 10.4 (10.6); depth at middle of
palate, 13 6— (14.0); maxillary
toothrow (alveoli), 11.6 (12.0).
Note. Four >specimens (Nos. 1 74-">: >l —1 ) collected at Textlananquila
on Mount Iztaccihuatl, above Amecameca, and presented to the U. S.
National .Museum by Professor Ferrari -Perez, arrived in Washington
after this article was in type. They entirely confirm the identity of
"
Romerolagus dinzi and R.
" nelsoni .
—Gerrit S. Miller, Jr.
*
I ii view of Mr. Nelson's personal acquaintance with the region where the two
types were collected I requested him to give me a brief accountof the geography. This
"
he lias kindly done as follows: The total area occupied by Rnmerolagus appears to be
limited to the middle slopes of the volcanos Popocatepetl and Iztaccihuatl. The
boundary line between the states of Mexico and Puebla runs along the crests of these
mountains in a northerly and southerly course, thus placing the western slopes in
Mexico and the eastern ones in Puebla. These mountains are joined by a broad ridge
about 12,000 feet high, at each end of which rise the high peaks. The middle slopes,
where Roirn rolagus lives, are continuous around both mountains and lie in an area 20
miles long, in a north and south direction, and ten miles broad, from east to west.
Romerolagus lives permanently only where it has the shelter of the coarse saccaton
grass and the areas occupied by this plant are broken by hot slopes on which it can not
maintain itself. These breaks are not wide and can be readily crossed by small
mammals. The extremely limited area which Romerolagus occupies, and the absolute
identity of climatic and other physical conditions within it, appear to preclude the
possibility of the existence of more than one local form."