VERTEBRATA. 19 



face rather short. Cutting teeth ~~ ■. upper elongate, far apart, rather curved ; lower 

 shelving, front pair conical, small, shorter than the middle pair, which are elongate, curved, 

 acute , the hinder smallest and shortest. Canines none. Grinders £=, the front 3.3 in each 

 jaw, small ; the hinder 4.4 large, square, acutely tubercular. 



The skull is shorter, broader, and the face less elongated than that of the different 

 species of Tupaia, and it differs from them in the two front teeth of the lower jaw being 

 smaller and shorter than the succeeding one, while in all the species of Tupaia (including the 

 genus Dendrogale) figured by Temminck, the four front teeth of the lower jaw are equally 

 elongated. The hinder cutting tooth in the upper jaw is placed on the suture of the inter- 

 maxillary (and hence may be a true canine) and not in front of the suture of the inter- 

 maxillary, as is the case with the skull of Tupaia tana and T. ferruginea in the British 

 Museum collection. 



Borneo may be regarded as the proper home of the subfamily Tupaina, as it possesses 

 all the genera, Tupaia, Hylomys, and one which, from the form of its tail, may be called 

 Ptilocercus. 



The true Tupaia have a broad hairy tail like the squirrels ; the Hylomys have a very short, 

 slender, cylindrical tail, covered with short close adpressed hair ; and the Ptilocercus, on the 

 other hand, have an elongated cylindrical tail, covered with rings of square broad scales, 

 like the long-tailed rats, but the end of the tail is furnished with a series of rigid hairs on 

 each side, like the barb of an arrow. I may remark, that besides the genera here noticed, 

 the Dutch naturalists have described an animal under the name of Hylogalea murina, Verh. 

 Mamm. t. 26. f. 3. t. 27. f. 17-18, also from Borneo, which differs from the Tupaia (or 

 Hylogale) in having a cylindrical tail covered with short hair, but furnished with a pencil of 

 longer hair at the tip, which I propose to separate from the other under the name of Dendro- 

 gale. Each of these genera has a peculiar livery ; the Tupaia are grizzled yellow and brown, 

 with a yellow streak across the shoulders ; the Hylomys are uniform dark-coloured ; the 

 Dendrogale and Ptilocercus have no shoulder-streak, but a dark streak on the side of the 

 face inclosing the eyes ; the former having a white spot on the forehead not observed in the 

 latter. 



At first sight Ptilocercus has much the appearance of a marsupial animal allied to 

 Cuscus, but this resemblance proves to be only in the mere external form, when the characters 

 are examined, as, for example, it wants the large great-toe of that group. 



The skulls of Tupaia and Ptilocercus have a considerable resemblance to those of the 

 LemuridcB, and particularly in having the orbits entire. The Tupaia are peculiar in having 

 a large elongated aperture on the hinder-part of the middle of the zygomatic arch, while the 

 Ptilocercus has only a small round perforation in the front part of the middle of the same 

 part, which is probably the analogue of the hole in the former genus. 



