388 



VERTEBRATA. 





THE HYSTRICID.E. 



This family embraces a number of tribes, all bearing more or less resemblance to the well-known 

 Porcupine, whose scientific name is Hystrix, and thus furnishes the title of the group. Most <>t 

 these have some resemblance to the hog, from the nature of their hair, the form of their body, 

 and their manner of walking, as well as in some less important particulars. Their size, though 

 than that of the hog, is still superior to most other rodents. They all have four pair of molar 

 teeth, the crowns of which exhibit sinuosities more or less complicated. The cranium and jawfl 

 also present some peculiarities. The tribes included in this family we shall notice under the 

 names of Caviens, Celogenyem, Dasyjiroctiens, Hystriciens, Aulacodicns, Erethizoniens, Chinchil- 

 liens or ( "nlhninfi ax, ano! Anomaluriens. 



THE CAVIENS OR CAVIINA. 



This tribe has the following characteristics: molar teeth rootless, divided by folds of enamel 

 so as to form lohes having acute angles; the series of molars on opposite sides of the upper yw 

 converging, and nearly meeting in front; incisor teeth comparatively short, those of the lower 

 jaw not being extended backward as far as the springing of the angular portion, or descending ' 

 ramus; four toes to the fore-feet, and three to the hind; tail wanting, or rudimentary; uppei 

 lip entire; a strongly-developed horizontal ridge on the outer surface of the lower jaw; the 

 angular portion of this jaw produced much beyond the condyloid portion, descending below, 

 the level of the dental portion, and with a curved lower margin; clavicle- wanting. 



