42 MR. R. I. POCOCK ON THE EXTERNAL 



The only example of L. ruhriventer examined, namely a female, 

 had the skin of the circumanal area distinctly bnt not strongly 

 wrinkled. On the other hand, some females of L. viongoz show 

 no sign of wrinkling, others show traces of it, and in some 

 males the wrinkling is rather strongly pi^onounced. A complete 

 gradation therefore in the development of the glandular area can 

 he traced from L. coronatus through L. mongoz to L. macaco and 

 L. alhifrons (text-fig. 12, A-C). 



The paired anal glands, so well known in some orders of 

 Mammals, e. _r/. the Rodentia and Carnivora, appear to be absent 

 in almost all Lemurs. The only genus in which I have found a 

 trace of them is Chiromys, where they are represented by a pair 

 of small, shallow invaginations, one on each side of the anal 

 orifice. 



The External Genitalia of the Male. 



According to Milne-Edwards and Grandidier each of the three 

 genera of Indrisidse may be characterised by the structure of the 

 penis and baculum. The penis appears to be short, subcylin- 

 drical, and apically truncated, and the baculum is distally 

 biramous in all cases. 



In Lichanotus the epithelium is striated, and there are on each 

 side of the organ near the middle of its length two strong 

 recurved spines set one above the other. The baculum is greatly 

 expanded at its proximal end and gradually narrows from the 

 thickening to the middle of its length. From that point the two 

 sides diverge gradually to the apices of the two branches, which 

 themselves diverge evenly at about an angle of sixty degrees, 

 each branch being rather less than one-third of the length of the 

 whole bone. 



In Indris the epithelium of the penis is ii-regularly reticulated, 

 and on each side of the organ there is a patch of rather small 

 spines set in three irregularly vertical rows which extend also to 

 the underside. The baculum differs from that of Lichanotus in 

 being thicker in the middle of its length, without any proximal 

 (or basal) expansion, and in having the two bi^anches much less 

 divergent and a little longer, each slightly exceeding one-third 

 the length of the entire bone (text-fig. 14, C). 



In Projnthecus the epithelium of the penis is grooved and beset 

 with minute spicules. The baculum differs from that of Indris 

 in having the branches very long, each being more than half the 

 length of the entire bone, longer, that is to say, than the stalk 

 instead of shorter as in Indris and Lichanotus. 



The penis of Ghirogaleus major (text-fig. 13, I, K, L) is rather 

 short and broad, nearly parallel -sided, with an ovate extremity 

 giving it a somewhat linguiform appearance from the lower or 

 upper view. It is longitudinally grooved and closely punctured, 

 the punctures possibly marking the position of minute spicules 



