96 MR. E. R. ALSTON ON THE ORDER GLIRES. [Jail. 18, 



pital processes short. Upper grinding- teeth with one internal and 

 three or four external folds, the latter soon separated as isolated 

 enamel-loops ; the lower teeth similar but reversed. 



2. Ccelogenys, F. Cuvier, Ann. du Mus. x. p. 203 ... (1807). 



Muzzle obtuse ; skin of cheeks reflected below the zygoma ; hind 

 feet with five digits ; tail reduced to a tubercle. Skull with the 

 zygoma enormously inflated, the anterior two thirds composed of the 

 maxillary zygomatic process, which is hollowed out below into a 

 great chamber, lined with mucous membrane and communicating 

 with the mouth ; infraorbital opening with a canal for the nerve ; 

 paroccipital processes long. Upper grinding-teeth with two internal 

 and three external folds, except the third molar, which is reversed ; 

 lower teeth with one external and three internal folds. 



Family V. Dinomyidje. 



Incisors broad. Grinding-teeth rootless, with folds dividing them 

 into transverse lobes. Optic foramina confluent. Paroccipital processes 

 short. Palate broad. Clavicles imperfect. Manubrium broad. Upper 

 lip cleft. Hair harsh. Tail rather long, bushy. Both fore and hind 

 limbs with four digits ; claws as in the last family. Neotropical. Re- 

 cent genus : — 



1. Dinomys, Peters, Monatsb. Ak. Berlin, 1873, p. 551 (1873). 

 (Characters those of the family.) 



Family VI. Caviid^e. 



Incisors short. Grinding-teeth with folds dividing them into trans- 

 verse lobes. Milk-teeth shed during foetal life. Optic foramina 

 separate ; paroccipital processes long and curved ; palate contracted 

 in front ; mandible with a strong masseteric ridge. Clavicles im- 

 perfect. Upper lip entire; ears short or long; fur moderately soft ; 

 tail very short or absent. Fore feet with four digits, hind feet with 

 three only ; claws as in last family. Neotropical. Recent genera : — 



1. Cavia, Pallas, Misc. Zool. p. 30 {ex Klein, 1751) . . (176G). 

 Body plump; limbs very short, subequal; ears short; hind feet not 



palmated ; no external tail. Skull much depressed ; malar slender ; 

 palate much contracted in front, deeply emarginate behind, exposing 

 the prsesphenoid ; incisive foramina long. Grinding-teeth each divided 

 into two angular lobes. 



2. Bolichotis, Desmarest, Mammalogie, p. 360 (1822). 



Limbs and ears long ; tail very short or rudimentary. Skull less 

 depressed than in Cavia, and the facial portion comparatively larger ; 

 palate still more deeply emarginate, exposing the vomer ; incisive 

 foramina long. Grinding-teeth each divided into two angular lobes, 

 except the third upper molar and the lower premolar, which have 

 each three lobes. 



