228 Say on Isodon Pilorides. 



Natural Character. 



Clavicles robust, perfect ; incisores not narrowed at tip, but 

 very obtusely rounded • their transverse section presents a trian- 

 gular figure, of which the angles are rounded : molares sixteen, 

 the two series in each jaw converge a little towards the front, and 

 consist of four teeth in each series, prismatic, not divided at base 

 into radicles ; their crowns flat, and traversed equally from the 

 base to the summit by lamina, which on the summit and base of 

 the tooth terminate precisely alike, in zigzag lines, and are the 

 effect of the sides of the tooth being folded inwards transversely 

 and with but little obliquity ; the inner angles of the folds attain 

 or surpass the centre of the width of the grinding disk, and do not 

 oppose, but pass between the angles of the opposite folds ; each 

 molar of the superior jaw has two folds on the exterior and one on 

 the interior side, and of the inferior jaw there are two folds on the 

 interior side, and only one on the exterior; the interstices are filled 

 near the summit with a cortical substance, but at the base they 

 are void; the form of the grinding surface of the molares is qua- 

 drate, that of the two intermediate ones of each series particularly; 

 the anterior molares are a little oblong, those of the inferior jaw 

 terminate before in an angle ; the posterior tooth of each series is 

 somewhat rounded behind ; forefeet four-toed, with a small tuber- 

 cle instead of a thumb ; hind feet five-toed ; the toes are all di- 

 vided, and rest equally on the soil in walking. 



Species. 



1. Pilorides^ colour black, intermixed with testaceous on the 

 top of the head, back, sides, posteriors and outsides of the legs ; 

 the hair of these parts being pale cinereous at base, then deep black, 

 then testaceous, the tip black ; on the sides, particularly in the 

 region of the shoulders, are a few remote hairs, which are white 

 and somewhat thicker than the others ; front, sides, and inferior 

 portion of the head and of the neck, breast and line down the ab- 



