1890.] THE SECONDARY SEXUAL CHARACTERS IN HOMOPUS. 521 



5. Note on the Secondary Sexual Characters in the South- 

 African Tortoises of the Genus Humopus. By G. A. 



BoULENGER. 



[Received June 9, 1890.] 



I owe to the kindness of Mr. J. M. Leslie, F.Z.S., of Port Elizabeth, 

 two fully adult hving specimens of Homopiis areolatus, male and 

 female, which I have the pleasure of exhibiting before the meeting. 

 They were sent to me in illustration of the fact that the male is 

 armed on the back of the thighs with a bony tubercle, which I stated, 

 on the evidence of the specimens in the British Museum, to be absent 

 in that species. The tubercle is, however, comparatively small and 

 rounded, not conical, verj' much less developed than in H. femoralis 

 and H. s'ujnatus ; it is to bo found, but in a quite rudimentar}' con- 

 dition, in the female from Port Elizabeth. 



It may be well, on this occasion, to point out the very marked 

 external characters which distinguish the fully adult male : — First, 

 the size of the head, which is much greater, as may be seen from the 

 measurements given below. Second, the shape of the snout ; the 

 beak ends in a much stronger point, and its profile descends slightly 

 forwards, whereas in the female the profile slants in the opposite 

 direction. Third, the much greater length of the mandibular sym- 

 physis, which measures nearly half the total length of the mandible, 

 as against about one third in the female. Fourth, the greater size 

 of the large detached scale on the inner side of the elbow. And 

 lastly, in this specimen, but not in the others I have hitherto ex- 

 amined, the presence, on the upper side of the tail near its end, of a 

 smaU bony tubercle similar to that on the hinder side of the thighs. 

 The plastron shows no concavity whatever. 



On comparing this male specimen with specimens of the same sex 

 of U. femoralis and H. sifjnatus, I find that it differs from them in 

 the following points, apart from the characters which I have given 

 in the Catalogue of Chelonians : — From H. femoralis in the much 

 longer mandibular symphysis (see measurements below) and the 

 much smaller size of the femoral tubercle : from H. signatus in 

 both the above characters and in the absence of a plastral concavity, 

 which is well marked in the male of that species. 



Measurements, in millimetres. 



Length of carapace 



Length of plastron 



Length of head 



Width of head 



Length of mandible 



Length of mandibular sym 



physis 



Length of femoral tubercle 



