[6 5 .] 1. D iplostoma? bulbivorum. (Rich.) Camas-Rat.
Öenus. Diplostoma. Rafikesqtte-Smaltz ? (Desmarest, Mamm.)
P late x v iii B.
There is a specimen of a quadruped in the Hudson’s Bay Museum, which
Mr. David Douglas informs me is the; animal known on the banks of the Columbia
by the name of the Camas-rat, because the bulbous root of the Quaraash or Camas
plant (Scilla osculcnta) forms its lavourite food. The scull is wanting, and the
animal, therefore, cannot be with certainty referred to a genus, but the form of
its exterior cheek-pouches leads me to think that it may belong to the diplostoma of
M. Rafinesque-Smaltz. There is, howéver, a discrepancy in the number of its
toes and in the presence of a tail, which, if M. Rafinesque’s specimen was perfect,
is decisive against this arrangement. The characters of the genus diplostoma, as
quoted by M. Desmarest, are as follows :—■
Diplostoma (Am. Month. Mag. 1817.)—Mouth double ; the exterior one
formed by two great pouches, which extend as far back as the shoulders, and
meet before the incisors, all of which are furrowed; four molar teeth of a side
in each jaw; body cylindrical; neither tail nor ears; eyes hid by the fur; four
toes on each foot. This genus is nearly allied to that of. thé .mole-rat, but differs
in its cheek-pouches, and in the number of .its toes. Two species were discovered
by Bradbury on the Missouri. They live beneath the surface of the earth and eat
roots. The early French travellers named them gauffres.”
D E S C R I P T IO N .
Form.—Body like that of a great mole, with a head that appears large and clumsy owing
to the swelling out of the cheek-pouches. The hose being margined by a slight prolongation
of the superior edge of the cheek-pouch appears flat and broad, but its tip and nostrils are
comparatively small; it does not project in the least beyond the plane of the incisors.
The incisors are entirely exserted, are stronger than those of the musk-rat, and have three
convex sides. The anterior side is the broadest, is without grooves, and has a yellowish
colour. The upper incisors have even cutting edges, and project forwards and downwards
immediately from under the nostrils, instead-of standing out from a cleft in the upper lip.
The lower ones are linear, with round tips, and project nine lines above their sockets, being
longer than the upper ones. The true mouth is a vertical slit, nearly an inch long, situated
Bibliskad by John, Murray. January 18Z9.