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Show 20 ::;EXUAL SELECTION. J'AllT ll. 1 b' 32 in which the sexes arc with the dull-colonrec. go leS, d n- ~ 'se with the not known to differ m colo?r, a~t I \.e:~~lcs bceomo st1c1debtteh (Ga. tero. tcus), m wlnch t~1e < rrJ c b :niantly coloured during the spawmng-sca.son. . ~. Ill <of the smooth-tailed stickleback (G. lewnts) p: rl-. rna . 1 d · f a nurse w1l1 forms clurino- a long tll11G t 10 ntws o . . 11 0 d · ·1 cc and IS contwua Y cxcmphry care an VJgJ an ' < t tl em])lo)·~cl in gently leading bacl-:: the young o lle nest when they stray t oo f ttr.. He couraob· eous .y c.h·ivcs away all enemies, including the fema~cs of lus . . , , It would indeed be no Rmall rchcf to the O\\ n species. . . ] o·o- wer male if the female, after depositmg 1~r cb~s, . . immediately devoured by som enem~~ for he 1 IS foiCec incessantly to drive her from the nest.. . . . ' rrhe males of certain other fishes mhabJtmg _S<~uth America and Ceylon, and bolongin_g to two ~hs~mct l b the extraonlin·trv habit of hatclung the ore, crs, ave ' • h' 1 eggs laid by the females witltin their mo~ths or_branc Ja cavi· t.·J es. :14 With the Amazonian speCies wlnc1h · fodl low this habit, the males, as I am informed by the \.1~ ness of Professor Agassiz, "not only arc genel:ally brighter ':than the females but the difference IS greater at "the spawning-seas'o n than at any otl 1er t1' me. , rrh.c , species of Geophagns act in the same manner ; and _m this o-enus a conspicuou protuberance becomes d~,eloped on the forehead _of the m~les during th~ breedm·g~ season. With the varwus speCies of Chro1mds, as Pro fc~"Sor Agassiz likewise informs me, sexual differences a2 Cuvier 'R~"'ne Auimul,' voL ii. 182D, p. 212. . a~ 'ce 1\1;. wn7-in<Yton's mosl inleresling de. cription of the h alJ:is of the ~a~lerostett$lei'U~·us, in' Annab nnu Mag. of Nat. Bitit.' ~ovcnil.>,·r, 18:i5. · • s t 1r: 18T a1 J>rof. Wymn.n, in 'J>roc. Do~ton Soc. of Nnt. H1st., ep; ;,, 8·G~· Also \\'. 'rurner, in 'Journal o( Annt01uy nnu Phy,. ~01 • 1, 1 • p. iS. Dr. Gunther hns likeiYise ucscr:bcu oth'cr en scs. CII .I.l'. xu. FISHES. 2l in colour may be observed, "whether they lay their " eggs in the water among aquatic plants, or deposit " them in holes, leaving them to come out without "fnrthcr care, or build shallow nests in the river-mud, "OYer which they sit, as our Promotis does. It ought "also to be observed that these sitters are among the ':brightest species in their respective families; for "instance, Hygrogonus is bright green, with large "black ocelli, encircled with tho most brilliant red." \Vhether with all the species of Chromids it is the male alone which sits on the eggs is not known. It is, however, manifest that tho fact of the eggs being protectcu or unprotected, has ltad little or no influence on the differences in colour between the sexes. It is further manifest, in all the cases in which the males take exclusive charge of the nests and young, that the destrnction of the brighter-coloured males would be far more influential on the character of the race, than the destrnction of the brighter-coloured females; for the death of the male during the period of incubation or nursing wonld entail tho death of the young, so that the. e eould not inherit his peculiarities; yet, in many of the. c very cases the males are more conspicuously coloured than the females. In most of the Lophobrn.nchii (Pipe-fish, Hippocampi, &c.) the males have either marsupial saeks or hemispherical depressions ou the abdomen, in which the ova laid by the female are hatched. The males al ·o shew great attachment to their young.35 The sexes do not commonly differ much in colour; but Dr. Gunther believes that the male Hippocampi are rather brighter than the f<c3males. The genus Solenostoma, a;; Ynrrcll, 'IIist. of Dl'itish Fishes,' vol. ii. l 836, p. R2D, 338. |
