ON SOME LIZARDS OF THE GEXUS CHALCIDES. 



77 



6, On some Lizards o£ the Genus Clialcldes. 

 By E. G. BouLENGER, F.Z.S. 



[Received February 4, 1920 : Read February 24, 1920.1 

 (Text-figures 1-4.) 



At a recent meeting of the Society a paper was read by Major 

 Stevenson-Hamilton in which the subject of the geographical 

 distribution of the varieties of various African mammals was 

 touched upon, and it was pointed out that one would be justified 

 in treating some of the varieties as distinct species were it not 

 for the existence of intermediate forms. This paper brought to 

 my mind some notes I had made about ten years ago on the 

 classification and distribution of the tSkink Chalcides ocellatKS, a 

 species inhabiting Southern Europe, Northern and IST. -Eastern 

 Africa, and S.W. Asia, which presents an extraordinar}^ amount 

 of variation : in fact, the structural difterence between the two 

 extreme forms is so great that, were it not for the wonderfully 

 complete manner in which they are connected, they could not 

 possibly be denied specific rank. I have recently gone over 

 again the mateiial in the British Museum, and completed my 

 notes on this subject, which I now have the honour to bring 

 before the Society. 



In papers written nearly 30 years ago my father, dealing with 

 the matter, came to the conclusion that this species could be 

 divided into five distinct varieties or subspecies, characterized 

 mainly by the coloration and by the number of scales round the 

 body, which was found to vary between 24 and 40 — a range of 

 variation far greater than is to be found in any other lizard *. 

 The five forms then described were the forma tyiyica^ and the 

 varieties ragazzii, tiligugu, vittaius, and 'polyle'pis . To these must 

 be added the var. occidentalis {Ch. simovyi Stdr.). 



The position of the nostril has been used as a specific character 

 in the lizards of the genus Chalcides, the sjDecies viridanus, of the 

 Canary Islands, and bottegi, of Somaliland, being regarded as 

 specifically difierent from C. ocellatus, mainly from the fact that 

 the opening is pierced in advance of the suture between the 

 rostral and the first labial instead of exactly above it, as is 

 normally the case in the typical C. ocellatus. C. bottegi was 

 described from a single specimen preserved in the Genoa Museum, 

 and was stated to be closely related to C. ocellatus, but differed, 

 apart from having the nostril pierced in advance of the rostral 

 and first labial, in the body being much more slender and the 

 scales of the vertebral rows being more than twice as broad as 



*- Bouleuger. Ann. & Mag. N. H. (6), v. 1890, p. 144. 

 „ Tr. Zool. Soc. xiii. 1891, p. 138, pi. xvii. 



„ Ann. Mus. Genova (2) xii. 1891, p. 12. 



„ „ xvi. 1896, p. 551. 

 Anderson. Zool. Egypt, Rept. p. 210 (1898). 



