162 THE PREHENSILE PORCUPINE. 



From what we know already of the laws which regulate 

 the geographical distribution of animals, it might be pre- 

 sumed that these spine-coated Rodentia would include dif- 

 ferent genera, requiring only the means of instituting the 

 necessary comparisons in order to bring their distinctive cha- 

 racters to light. This has been effected in a great measure by 

 the labours of M. Fred. Cuvier, who has separated from the 

 genus Hystrix of Linnaeus, the Java porcupine, under the 

 title of Acanthion ; the Canada porcupine, or Urson of 

 Buffon, under that of Erethizon ; the Brazilian porcupine, 

 under that of Sphiggurus : and for the Mexican species, de- 

 scribed and figured in the present Number, he proposes the 

 generic name of Synetheres, as preferable to that of Coendus, 

 originally given to it by the Count Lacepede. 



The Coendou is an animal altogether peculiar and distinct : 

 no other species resembles it in its general forms. Its gait 

 is as heavy and ungraceful as its proportions, notwithstand- 

 ing it is endowed with an additional locomotive organ to those 

 usually granted to the Rodentia, viz. a prehensile tail. But 

 it is in the shape of the head and muzzle that it is more espe- 

 cially remarkable. All that part which corresponds to the 

 brain is raised and expanded so as to announce a most highly 

 developed cerebral organ within ; but this is in reality no 

 larger than in other Rodents. The phrenological character 

 is here produced by large sinuses, which extend in every 

 direction over the frontal bones, covering the brain anteriorly, 

 and augmenting the extent of the organ of smell ; for these 

 cavities communicate with the nostrils. The muzzle presents 

 a thick obtuse fleshy projection, in front of which are the ori- 

 fices of the nostrils, of a very simple form. In all these re- 

 spects there is no resemblance between this animal and the 

 porcupine ; and the same characters serve even better than 

 the prehensile tail to separate it from every other Rodent, being 

 indicative of a fundamentally different nature, peculiar habits, 

 and consequently the type of a distinct genus. But if by its 

 physiognomy it is found isolated from all the other known 

 species of its class, it nevertheless appertains in its denti- 

 tion, like the other spiny genera, to the omnivorous Rodentia 

 with compound teeth. 



The Coendou has four molaries on either side, both in the 

 upper and the lower jaw, which diminish in size from before 

 backwards : their structure is analogous to that of the Urson 

 shown at fig. 9. of the Plate of dentary characters in the pre- 

 sent Number. 



The external conformation does not indicate a lively or pre- 

 dominant sensibility in any of the organs of sense. The eyes 

 are small and prominent, and their pupil, which can only be 



