6 MR. W. F. R. WELDON ON CAI.LITHRIX GIGOT. [Jail. 15, 



I may remark in conchision another interesting embryonic feature 

 of Tetraceros, namely the fact that it is, so far as I know, the only 

 ruminant except Moschus with a uniserial psalterium '. 



2. Notes on Callithrix gigot. By W. F. R. Weldon, B.A. 



[Received December 12, 1883.] 



In September last a specimen of the rare Monkey Callithrix 

 gigot, Spix, died in the Society's Gardens, and came into my hands 

 for dissection. It seems to" me that a few short notes on its 

 anatomy may be of use. 



External characters. — The hair was long and soft, slightly woolly 

 over the trunk. On the forehead it was shorter and more thickly 

 set ; over the limbs short and loose. The general colour of the 

 dorsal surface was reddish grey, redder beliind, more ashy over the 

 forehead and limbs. A typical hair from the back was about two 

 inches long ; black at the root for half an inch, then cream-coloured 

 for three quarters of an inch, the tip being ringed with chestnut and 

 black. 



The muzzle and chin were black, with a few short, strong, white 

 hairs ; a black line ran up the nose and round the eyes, the lids of 

 which were white with black lashes. The long hairs of the brows 

 were black. The forehead was thickly covered with pale grey hairs, 

 slightly tipped with black ; and a faint black ridge ran across it 

 between the ears. 



The ears themselves were black, covered with short black hairs, 

 except for a small grey tuft at the postero- external angle. 



In front of the ears a very light grey hand passed over the cheek, 

 being continued above on to the forehead, below on to the chest. 



The throat was naked, the skin in this region being of a bright 

 pink colour. 



The limbs had their inner surfaces pale grey, while the hands and 

 feet are^black. 



The tail was red, the hair being more bushy at the base than at 

 the apex, which might, however, be an effect of friction during con- 

 finement. 



The dimensions of the specimen, which was a young female, are 

 given below : — 



foot, inclies. 



From muzzle to root of tail, over hack. ... 1 2 



From chin to anus, over belly 1 1 



Length of tail, including hair 1 1 1 



From occiput over forehead to upper lip . . 3| 



Breadth of nasal septum -^^ 



From nostril to inner canthus ^ 



' See Professor Gan-od's valuable remarks nn the arrangement of this 

 structure, P.Z.S. 1877. 



