CHARACTERS OF THE LEMURS AND TARSIUS. 



47 



being concave close to the base, then convex, then strongly con- 

 cave owing to the upeurling of the distal fourth of its length. 

 The ventral side is curved in correspondence. No other 

 Lemuroid known to me has a strongly upcurled tip to this bone. 



In connection with the scrotum there is one fact to be re- 

 corded. In Lemur catta this sac is always naked (text-fig. 12, D). 

 In all other species of Lemuroid Primates it is clothed with hair 

 normally (text-figs. 12, A, B; 16, A). Occasionally the postero- 

 inferior portion is naked, as I have noticed in one or two specimens 

 of Galago ; but I have no doubt that in these cases the absence 

 of the hair was due to rubbing. 



The External Genitalia of the Female. 



In the standard text-books of Mammals published even as 

 recently as Max Weber's in 1904, it is stated that the urethra 

 traverses the clitoris in the Lemuroidea. This is not true of any 

 Madagascar Lemur I have examined, and applies only to the 

 Asiatic and African forms. In the Madagascar species the 

 urinary orifice opens at a varying distance between the vaginal 

 aperture and the apex of the clitoris, generally much closer to 

 that orifice and only in one case, Lemur catta, a little nearer the 

 tip of the clitoris. 



Milne-Edwards and Grandidier have shown that the clitoris 

 varies considerably in form in the three genera of Indrisidse. 

 In Lichanotus (Avahis) it is long, pendulous, and narrow, and 

 parallel-sided in its distal two-thirds, but expanding proximally 

 towards the orifice of the vulva. From the orifice of the urethra, 

 situated a little below the vulva, a groove extends towards .the 

 tip of the clitoris, arid at the extreme tip of the latter is placed 

 the aperture of a glandular depression. 



In Propithecus the clitoris is much shorter and thicker, with 

 a broadly rounded distal end carrying a glandular orifice. The 

 aperture of the urethra lies approximately midway between the 

 orifice of this gland below and of the vagina above. In Inclris 

 the distal end of the clitoris is gradually and widely expanded 

 laterally and extended considerably beyond the orifice of the 

 gland, but the orifice of the urethra is situated even nearer to 

 the vulva than in Lichanotus. 



In the species usually referred to the genus Lemur there is 

 considerable variation in the structure of the genital area of the 

 female. 



In Lemur varius the clitoris is a short, thick, fleshy excrescence 

 with a blunt apex and somewhat cordate in shape, rising from 

 the centre of a tolerably large area of naked skin. Its free 

 posterior surface is marked by a median groove or rima defined 

 laterally by a pair of thick labia. When the latter are separated 

 the urinary channel, a gutter with thin elevated margins, is 

 displayed. In a mated female this gutter is seen to lead from 



