CHAMJELEONS. 
99 
in a very subordinate manner only. This defect is compensated 
by tbe development of an additional sharp denticle at the inner 
base of each claw, and of a spine vertically projecting from tbe 
flexor side of each finger and toe, which must immensely 
strengthen the power of the animal for holding on to branches.’ * 
Dr. Gray’s list, f published in 1864, enumerates thirty species 
of Chamaeleons (or an average of two species to each of his 
genera). More than a dozen others have since been added. 
It is very necessary to note, in our study of the variations 
to which the species of Chamaeleons are subject, the secondary 
sexual characters which they display more strikingly than any 
other reptiles. Mr. Darwin,} in his account of selection in 
relation to sex, thus treats this division of his subject : — 
* In the genus Chamseleon we come to the climax of dif- 
ferences between the sexes. The upper part of the skull of the 
male C. bifurcus, an inhabitant of Madagascar, is produced into 
two great, solid, bony projections, covered with scales like the 
rest of the head ; and of this wonderful modification of structure 
the female exhibits only a rudiment. Again, in Chamceleon 
Owenii from the West Coast of Africa, the male bears on his 
snout and forehead three curious horns, of which the female 
has not a trace [see PL iii. figs. 6, 7]. These horns consist of an 
excrescence of bone covered with a smooth sheath, forming 
part of the general integuments of the body, so that they are 
identical in structure with those of a bull, goat, or other 
sheath-horned ruminant. Although the three horns differ so 
much in appearance from the two great prolongations of the 
skull in C. bifurcus, we can hardly doubt that they serve the 
same general purpose in the economy of these two animals. 
The first conjecture which will occur to every one is that they 
are used by the males for fighting together ; but Dr. Gunther, 
to whom I am indebted for the foregoing details, does not 
believe that such peaceable creatures would ever become pug- 
nacious. Hence we are driven to infer that these almost mon- 
strous deviations of structure serve as masculine ornaments.’ 
Here we may refer to Ford’s beautiful figure § of C.Melleri . 
The snout of C. gallus , a small Madagascar species (Pl. iii. fig. 3), 
‘ has a long pointed, flexible appendage, w’hich is covered with 
large soft tubercles.’ In both these species the male only is 
known, as in the no less curious C. maltlie , C. brevicornis, and 
C. globifer. || 
* Zoological Society's Proceedings, 1874, p. 442 and PI. lvii. 
t In his Catalogue of Lizards, published in 1845, only eighteen species 
of Chamaeleons are mentioned. See P. Z. S., 1864, p. 465. 
X Descent of Man, vol. ii. 1871, p. 84. 
§ P. Z. S., 1864, PI. xxxii. It accompanies Dr. Gray’s Decision. 
|| Chamaeleons from Madagascar, described and figured by Dr. Giinther 
in P. Z. S., 1879, Part I. 
