OCR Text |
Show 36 SEXUAL SELECTION. PAnT II. . h. h will occur to ever.y one is that first conJecture w lC 1 .(! fighti.nO' to(l'ether; but d b tho rna es !Or 1 o o . they arc use y I< 'ndcbted for the foregomg Dr. Gunther, to whom . .am t~at such peacable crcadetails, does not beheve ci.O'lS Hence we are tures woul d ever b ec ome lmCoY na 'd r.i ven to infer that these almost monstrous deviations of structure serve as masculine ornaments. With many kinds of lizards, the sexes differ slightly in colour, the tints and stripes of the males ldng brighter and more distinctly de: finccl than in the Fig. 36. Chammleon Owrnii. Upper t1gure, male; females. This, for lower figure, female. instance, is the case 'tl tho lneviously-mentw. ned Cop. hotis and w0 it·hl t1h e Wl 1 ·s of S Afnca. In a OIC y us Acanthoclactylus capens~ 1. ·s either much redder or of the latter country,\ e m; et~e Indian Calotes nigrigreener than the fema e. .n . nco in colour between labris the~·c is a. gre~:~ro~~~~:e male are black, whilst the sexes , the hps a In our common those of the female are green.. . ) "tho under 1itt1o viviparous lizard (Zootoca vw~p;r~n the male arc ': side of tho body and base ~f the ln.~. in the female "bright orange, spotted w~th blacl'", .t·l t spots."~7 t ale greyish-green WI , lOU " these par s are P< ' f Sitn.na possess a vVe have seen that tho males alone o u7 Dell, 'History of British Reptiles,' 2nd c<lit. 1840, p. 40. CHAT'. XJI. UEP1'ILE ', 37 throat-pouch ; and this is splendidly ti11toJ with blue, black, and reel. In the P1·ociotret~~s ienuis of Chile the male alone is marked with spots of blue, groeu, and coppery-red.~8 I collected iu S. America fourteen species of this genus, and though I neglected to record the sexes, I observed that certain incli vi duals alone were marked with emerald-like green spot~, whilst others had orange-coloured gorges; and these in both cases no doubt were the males. In the foregoing species, the males are more brightly coloured than the females, but with many lizards both sexes arc coloured in the same elegant or even magnificent manner; and there is no reason to snppose that Emch conspicuous colours are protective. vVith some lizards, however, the green tints no doubt sel'Ve for concealment; and an instance has already been incidently given of one species of Proctotretus which closely resembles the sand on which it lires. On the whole we may conclude with tolerable safety that the beautiful colours of many lizards, as well as various appendages and other strange modifications of structure, have been gained by the males through sexual selection for the sake of ornament, and have been transmitted either to their male offspring alone or to both sexes. Sexual selection, indeed, seems to have played almost as important a part with reptiles as with birds. But the less conspicuous colours of the females in comparison with those of the males cannot be accounted for, as Mr. Wallace believes to be the case with birds, by the exposure of the females to danger during incubation. os F or Pmctotretus see 'Zoology of the Voyage of the "Beagle:" Reptiles,' by 1\fr. Boll, p. 8. For tile Liz(uds of S. Africa, see 'Zoology of . Africa: Reptiles,' by Sir Andrew 'mith, pl. 25 and 30. For tho lnllinn Culotcs, ceo' Reptiles of British lmlin,' by Dr. Giiuther, p. 1!3. |