16 Mr. Holberton’s and Mr. Yarrell’s 
folds more or less obliquely angular, and were not inaptly compared, 
originally, to the rug of earth-worms, or the rings of the aspera arteria. 
See Elliotson’s Translation of Blumenbach’s Physiology, Section 212. 
Mexican Doe, young. Canis familiaris, var. Mericanus. 
Length from mouth to anus 13 inches; whole length of intestines 5 
feet 4 inches; cecum 2 inches, of the ordinary form. Dentition irre- 
gular and imperfect; no apparent cause of death. 
JerBoa. Dipus Sagitta, Gmel. 
When divested of its skin, the form of the head in this animal is 
peculiar. The upper surface of the cranium is nearly square; the mas- 
toid processes are unusually large, excavated, and their parietes diapha- 
nous. They occupy the whole space behind the zygomatic arch on 
either side, and extend beyond the occipital bones backwards, and even 
with the surface of each parietal bone upwards. From the anterior 
portion of the nasal bones to the occipital ridge was 1 inch ,°;; from the 
anterior surface of the malar bone to the back of the mastoid process of 
the same side 1,4;; the width of the head between the edges of each 
zygoma 1,%;; behind the zygomatic arches % of an inch; across the 
mastoid processes 1 inch; mastoid cells projecting backwards beyond the 
occipital surface 4 of an inch. 
The meatus aes directed backwards; the malar bones so deep 
in front that vision is confined to the lateral and backward directions. 
The masseter muscle, large, arising from the under edge of the zygoma and 
orbit, passes downwards and backwards to be inserted into the base, angle, 
and ascending plate of the inferior mazilla; raising, bringing forwards, 
and also giving a limited degree of lateral motion to the lower jaw. The 
muscle analogous to the temporal arising from the fossa in front of the 
orbit, passing under the zygoma, is inserted on the fore part and side 
of the lower jaw. The portio dura passed outside the muscle elevating 
the jaw, under the edge of the zygoma to the angle of the mouth to be 
distributed over both lips. The branches of the infra-orbital nerve were 
distributed in the usual manner. The reason for noticing these nerves 
was on account of their unusually large size. 
