322 Monograph of the Genus Semnopithecus. 



with an immediate link of union between the long tailed monkeys 

 of India and Africa. The genus Colobus in fact appears to be 

 related rather to the Semnopitheci than to the Cercopitheci, 

 a group comprehending the typical Simiadce of the old world. 

 The Cercopitheci, or "guenons" of the French writers, have 

 the head tolerably round, but the forehead low, and the su- 

 perciliary ridge prominent; the muzzle projects, giving a fa- 

 cial angle of about 45°. Their form is spare and light, 

 their limbs and tail long, but in a much less degree than in 

 the Semnopitheci or Colobi, and the thumbs of the fore hands, 

 though short, are much better developed than in the Semno- 

 pitheci. The callosities are larger, the cheeks have ample 

 cheek -pouches, and the tubercles of the molar teeth are bold- 

 er and more acute. With respect to cheek-pouches in the 

 genus Colobus, it may be observed that Geoffroy St. Hilaire 

 states them to be tolerably well developed. Mr. Ogilby as- 

 serts that they are very large and distinct, adding that he was 

 "the more particular in making this last observation, because 

 the organs in question had not been previously recorded as 

 existing in the Colobi, and because M. Geoffroy St. Hilaire, 

 in his valuable lectures, even doubts their existence." The 

 words of M. Geoffroy are these; — "Leurs abajoues sont assez 

 developpees" We have ourselves carefully examined the dri- 

 ed specimen in which Mr. Ogilby considers the cheek-pouch- 

 es to be "extremely apparent and rather capacious," and 

 though we hesitate in differing from so discriminating and 

 judicious a naturalist, we cannot help confessing that we did 

 not feel satisfied on this point. The skin of the head and 

 face, in order to the preparation of the specimen, had evi- 

 dently been separated from the bones, and after the applica- 

 tion of the ingredients used in preserving it, returned to its 

 former position. In drying, a space would naturally inter- 

 vene between it and the bones of the jaws, and it would be 

 difficult to say, in a specimen so prepared, whether the vacu- 

 um thus presented indicated capacious cheek-pouches, or was 

 merely a consequence of the flaying of the head, and the sub- 

 sequent contraction of the skin in drying. The presence or 

 absence of these cheek-pouches, in dried specimens, is a very 

 difficult point to ascertain. 



The teeth of the Cercopitheci, furnished with more acute 

 tubercles, are adapted for grain, hard fruits, roots and insects, 

 those of the Semnopitheci for leaves and soft fruits, on which 

 these monkeys principally subsist. With this modification 

 of the dental system is associated a still more decided modifi- 

 cation in the structure of the stomach, at least on the part of 

 the Semnopitheci, which would hardly be expected. In the 



