117 



October 9, 1838. 



Rev. F. W. Hope in the Chair. 



The reading of a paper by Richard Owen, Esq., on the Osteology 

 of the Marsupialia, was commenced. 



Mr. Martin drew the attention of the Meeting to the crania of 

 tlie Sooty and White-eyelid Monkeys, Cercopithecus fuliginosus and 

 C. Mthiops, which were placed upon the table, and upon which he 

 proceeded to remark as follows : 



" It is now some years since I stated to the late Mr. Bennett that 

 in the skeleton of a Sooty Monkey I had discovered the presence of a 

 distinct fifth tubercle on the last molar of the lower jaw; recently I 

 have observed the same fact in the skull of the Collared or White- 

 eyelid Monkey i^C jEthiops) circumstances of some interest, as this 

 tubercle appears to be always absent in the Ccrcopitheci, and also in 

 such as the Malbrouck, Grivet, and Green Monkeys, Sec, which have 

 been separated from the Cercopitheci under the subgeneric title 

 Cercocebiis, Geoff., the Sooty and the White-eyelid Monkeys being 

 included ; though, as far as we can see, on no feasible grounds, dif- 

 fering from the foregoing species, as they do, in physiognomy and 

 also in style of colouring. However this may be, the Sooty and 

 White-eyelid Monkeys approximate to their supposed congeners in a 

 more remote degree than has hitherto been supposed. Now with re- 

 gard to the genera, Semnopii/iectfs and Macactis, both of which are from 

 India, and the African genera Inmis and Cynocejihalus, this fifth tu- 

 bercle is a constant character and accompanied by the presence of 

 laryngeal sacculi; and in another African genus, viz. Colobus, a fifth 

 tubercle also exists, but whether accompanied or not by laryngeal 

 sacs is still to be determined. May not this fifth tubercle, it may 

 here be asked, bring the Sooty and White-eyelid Monkeys within the 

 pale of the 3/«ca<?2 ? and the question will bear considering. Our 

 reply, however, would be in the negative; for as we have ascertained 

 by dissection, the Sooty Monkey, at least, is destitute of larj'ngeal 

 sacs, (but has large cheek pouches) and we may readily infer the 

 same of the other species, its immediate ally. The relationship, as 

 it appears to us, between these t\vo animals and the Indian Macaci, 

 is that of representation. They have not indeed the muzzle so pro- 

 duced and the supra- orbital ridge so developed as in the J/acoCT ; 

 but in these points they exceed the African Guenons generally, and 

 are also we think stouter in their proportions. They appear, indeed, 

 to constitute a form, intermediate between the Macaci and Cercopi- 

 theci, on the one hand ; as are the Colobi between the Semnopitheci 

 and Cercopitheci on the other. What the Colobi of Africa are to 

 the Semnopitheci, these two monkeys (and others have jierhaps to 

 be added) are to tlie Macaci. With respect to the genus Cercocebus, 



No. LXX. — Proceedings of the Zoological Societv. 



