40 



MR. R. I. POCOCK OX THE EXTERNAL 



Iii connection with the fur-combing use of the pectiniform 

 mandibular teeth in the true Lemurs, it must be remembered 

 that the spatulate finger-tips and short nails of these animals 

 deprive the digits of the scratching power they possess in ordinary 

 mammals with narrow finger-tips and comparatively long claws 

 or nails. Only one digit in the Lemurs is functional as a 

 scratcher, namely, the second of the hind-foot, which is short 

 with small terminal pad and long semi-erect claw. Thus is 

 established a most interesting correlation of characters in the 

 Lemurs : — namely, the uselessness of the fingers for scratching 

 the fur, the modification of the anterior mandibular teeth to sub- 

 serve that end, and the differentiation of the sublingua to keep 

 these teeth clean from scurf and hair. Now in Tarsias the lower 

 mandibular teeth are not modified to form a comb. Possibly 

 they are employed for cleaning the coat, but their structure 

 makes them less liable to be clogged, and at the same time less 

 efficient instruments for the purpose than the corresponding teeth 

 of the typical Lemurs. Possibly, perhaps probably, for these 

 reasons, the sublingua is less differentiated and two of the digits 

 of the hind-foot, the second and third, are set apart as scratchers 

 and are capable of acting in unison, almost like the corresponding 

 united digits of the syndactylous Marsupials. 



The sublingua of Chiromys probably serves mainly the purpose 

 of keeping the gnawing-teeth free from woody fibre ; and, for 

 anything I know to the contrary, it may also cleanse them of 

 hair and scurf. But I am not aware whether these teeth are 

 used as a comb or not. At all events, in the case of this genus it 

 is interesting to note that the absence of the typical lemurine 

 dental comb is accompanied by well-developed claws and by fur 

 of a very different texture from that of ordinary Lemurs, since 

 it consists of a light underwool covered by long coarse hairs. 

 Possibly the usefulness of the claws in combing this fur has been 

 one of the principal guiding factors in their evolution from nails. 



The Anus and its Glands. 



In all the Lemuroids examined, with one exception, the anus 

 is situated in the normal position below the joint of the tail so 

 that the base of that organ, when depressed, closes over it. But 

 in Chirogaleus major it is placed below, or on the distal side of 

 the joint of the tail, so that when that organ is raised the anus 

 is carried up on its base (text-fig. 16, A). . 



Normally in this group, that is to say in Nycticebus, Perodic- 

 ticas, Galago, Chiromys, the Indrisidse apparently, and in Lemur 

 catta. variegatus, and coronatus, the perineal and circumanal areas 

 are covered with hair ; but in L. macaco, L. albifrons, and the 

 various forms such as nigrifrons, rufus, fulvus, cinereiceps, asso- 

 ciated with albifrons, these regions are covered in both sexes 

 with nearly naked, folded, wrinkled, and glandular skin, and 

 similar naked skin extends for an inch or so along the root of 



