278 Mr. "R. I. Pocock on 



(19) Otomys laminatus. 

 Otomys laminatus, Thos. & Schw. P. Z. S. 1905, i. p. 267. 



4. 5. 1. 45; 4. 8. 31. 5. Sibudeni, Zululand. (Riidd 

 Exploration.) 



An Otomys rather larger than typical irroratus with the 

 colouring of southern specimens of that species. The 

 dimensions are : — 



Head and body 180 mm.; tail 120; hind foot 30 ; ear 22. 



Skull : greatest length 43 ; basilar length 35 ; zygomatic 

 breadth 23; length of upper molar series 10; bullae 7'b. 



The extraordinary multiplication of laminaj in w, and rri 

 distinguishes this species at a glance from any other known 

 Otomys. 



XXXVIII. — On the Genus Cercocebus, with a Key to the 

 knoivn Species. By R. I. PocoCK, F.L.S., F.Z.S., 

 Superintendent of the Zoological Society^s Gardens. 



In Trouessart's Cat. Mamm., Suppl. p. 15 (1904), the 

 described species and subspecies of Cercocebus are referred to 

 two subgeneric groups, Cercocebus (s. s.) and Leptocebus. 

 The latter name appears here for the first time in literature 

 to replace Semnocebus, Gray (nee Lesson), restored by 

 Mr. Lydekker for C albigena, Gray, on the strength of the 

 blackness of the eyelids and the presence of an upstanding 

 crest on the crown of the head. Although considerable 

 latitude in opinion as to what constitutes a generic or sub- 

 generic character must be allowed, there seems to me to be 

 no particuLar reason for regarding elongation of the hairs on 

 the crown as of higher systematic value than elongation of 

 tiiose on the brow, the cheeks, or the end of the tail, features 

 which, happily, no one has as yet claimed to be more tlian of 

 specific importance within the group. 



As for the whiteness of the eyelids, this is most pronounced 

 in the western species (C. lunulatus, cethiopicus, fuii(/inosus) , 

 mucli less marked, or, according to Mr. Lydekker himself, 

 sometimes absent, in specimens referred to C. Ilagenbeckiy 

 and also, according to the same author, absent in C. albigena 

 liotlischildi. Moreover, in C. congicus and C. llamlyni the 

 eyelids are white, and, at least in C. llamlyni, whiter tlian 

 the skin of the face. Yet these two species are certainly 

 more nearly related to C. albigena Rothschildi than to any- 

 one of the three typically white-eyelidded species. 



