134 OBSERVATIONS ON THE ANATOMY OF 
produces one at a birth ; it lives on vegetable food ; it is 
easily domesticated^ and its flesh forms an esteemed article 
of food in the countries it inhabits. This animal has been 
known to European naturalists under the Brazilian name of 
Paca for more than 200 years, being described by Lery in 
1578. It was described and figured by Marcgrave under 
the same name in 1648; and Ray, Buffon, Cuvier, and 
other naturalists, have described it under the same title. 
Fred. Cuvier has called it Coelogenus (hollow cheek), from 
the deep groove under the broad zygomatic arch on each 
side of the head. The Paca is one of the largest known 
Rodentia, or Glires, and is distinguished from the other 
genera of that order, by having five toes on each of the 
fore and hind feet, and by the deep hollow in each cheek. 
Daubenton has minutely described the anatomy, and figured 
the internal organs, of many animals of this order from the 
New World, nearly allied to the Paca, as the Agonti, the 
Guinea-pig, &c. ; but he has not figured any of the soft 
parts of the Paca, — and the few observations he has given 
on its anatomy, being taken from a very young specimen 
not larger than a rat, are sometimes inaccurate, and are 
quite inapplicable to the adult animal. Pie states that only 
one branch came off from the arch oi* the aorta, whereas in 
the adult animal I have found two distinct branches, as in 
most other quadrupeds. He found the csecum not 2^ inches 
long, whereas in the adult it is nearly 19 inches in length. 
The whole intestinal canal he found to be 7 feet in length, 
whereas in the adult it measures upwards of 30 feet. 
Cuvier has enlarged Daubenton's measurements of the in- 
testinal canal, but neither he nor any succeeding anatomist 
appears to have added to our knowledge of the internal 
structure of this animal. As the very young specimen dis- 
sected by Daubenton wa« a female, tlie male Paci; to which 
