Dr. J. E. Gray on the Chamseleonidse. 341 



to pass into each other, might induce one to believe that they were 

 specific ; but they can hardly be even considered as local varieties, 

 for the same variation seems to occur in specimens from different 

 localities often situated far apart. 



There is considerable difference in the sexes, especially of the 

 horned species which, I believe, was first established in my ' Mono- 

 graph;' but this difference does not appear to be common to all the 

 species of the Horned Chameleons ; for while the females of C.Owenii, 

 C. bijidus, and C. Parsonii are hornless, the expansions on the sides 

 of the nose of C. pardalis, which are analogous to the horn in C. 

 bijidus, are as much expanded in the adult female as in the males of 

 that species. 



The female specimens are much more common in museums than 

 males ; they are perhaps more easily caught when they come to the 

 ground to deposit their eggs : and this appears more probable from 

 the fact that females containing eggs are often to be found among those 

 collected. In some cases, even where there is a series of specimens, 

 they are all females ; at least I have not, from the external appear- 

 ance, been able to discover a male of C. senegalensis or C. dilepis. 



Dr. Hallowell (Journ. Acad. Nat. Sc. Philad. vii. 99) thought at 

 one time that the occipital lobes were peculiar to the females ; I also 

 was once inclined to believe this might be the case, before I had 

 seen his remark, from observing that all our specimens of C. dilepis 

 appear to be females ; but I had the same difficulty in finding any 

 males of C. senegalensis or other allied species ; and M. A. Du- 

 meril specially observes that " the cutaneous prolongation is not a 

 character only of the female C. dilepis" (Arch, du Mus. x. 1/4). 



There is considerable variation in the distinctness and height of 

 the occipital crest in the specimens of C. vulgaris and in some other 

 species. This often arises from the animals having been kept in 

 confinement without (or with oidy a very limited supply of) food, until 

 the muscles have shrunk. This should make one careful in using 

 the height of the crest as a character, more especially as many of 

 the specimens in museums have been kept alive in confinement either 

 in the country which they naturally inhabit or in some other, as 

 collectors like to have them alive as pets. 



Yet the well-fed and fresh-caught specimens seem to vary con- 

 siderably in this particular ; for example, specimens of C. vulgaris 

 from India, as a rule, seem to have the occipital crest higher and 

 more arched than African specimens ; but still there are in the 

 Museum collection some African specimens which have quite as high 

 crests. 



Little attention seems to have been paid to the coloration of the 

 species, probably because the animal greatly changes its colour during 

 life ; and specimens in spirits of some species, such as of C. vulgaris, 

 offer many variations, from bright yellow to dark lead-grey. Yet in 

 some species the distribution of the colours, at least in specimens in 

 spirits, seems to form permanent specific marks, as, for example, 

 the lines or white spots or white bands on the sides of several species. 



The number of species has gradually increased. In my Mono- 



