436 MR. F. E. BEDDARD ON THE [Mar. 15, 



by : (1) the absence of the black superciliary band ; (2) the white 

 colour of the nose-spot and of the hairs upon the ears ; (3) the 

 presence of the occipital band ; (4) the grizzled colour of the forearm ; 

 and (5) by the restriction of the red on the tail to the proximal 

 half of its under side. 



The constancy of the above-mentioned characters in C. erythrotis 

 has been tested upon five skins, four of which, including the type, 

 are in the collection of the British Museum ; the other, belonging 

 to the Zoological Society, is that of a specimen that lived for four 

 years in the Gardens, and was mentioned by Dr. Sclater in his 

 monograph of the genus Cercopithecus (P. Z. S. 1893, p. 246). 

 This specimen is ticketed Fernando Po ; and the same locality is 

 assigned to the type and to two other skins in the British Mu.seum, 

 the remaining skin in that institution being labelled " W. Africa, 

 G. Burton." 



The last-mentioned skin was taken from a small and presumably 

 very young individual. The length of the body from the occipital 

 interaural area to the root of the tail is about 10|j English inches 

 (= 263 mm.), and the tail itself about 16 English inches 

 (400 mm.). It is thus a much smaller Monkey than the type 

 of C. sclateri, and proves beyond doubt that the coloration of the 

 young C. erythrotis is practically the same as the adult, except 

 that the back and tail are darker and less rufous. Hence it may 

 be inferred that the coloration of the type of C sclateri would 

 not have altered appi'eciably had the specimen lived to maturity. 



It is unfortunate that none of the British Museum skins of 

 C erythrotis are sexed. The one belonging to the Zoological 

 Society is a female ; and since the only known example of 

 C. sclateri is a male, it is conceivable that the differences 

 pointed out above are sexual. But the analogy of C cephus, 

 a nearly related form, in which the sexes are alike in colour, 

 affords no support to such a conception. Finally, it may be inter- 

 esting to point out that the principal points of difference between 

 C. sclateri and C erythrotis may be ascribed to a deficiency of red 

 pigment in the hairs upon the nose, the ears, and the greater 

 part of the tail. In fact G. erythrotis might with some justice 

 be described as an eiythristic form of C. sclateri, so far, at least, 

 as the areas named are concei-ned. 



4. Contributions to the Anatomy of the Lacertilia. — (1) On 

 the Venous System in certain Lizards. By Frank E. 

 Beddard, M.A., F.R.S., Prosector to the Society. 



[Received Februaiy 23, 1904.] 



(Text-figures 88-94.) 



I have found that the best method of studying the venous 

 trunks of these lizai'ds is to divide the anteiior abdominal vein 

 and then to inject both anteiiorly and posteiioily ; rio valves stop 



