The Annals and magazine of natural history; zoology, botany, and geology . er than in ThoUchthyes ofyounger age; but this is merely in consequence of the greaterdevelopment of the body in the more advanced stage, itsgrowth being much more rapid than that of the head. 2. Not only Chcetodon, but also other Squamipinnate ge-nera appear to have a TIwUchthys-stRgc. With the speci-men of Ch. citrinellus mentioned above, Hr. Godeifroy sentanother fish, represented in the accompanying woodcut, andnow in the British Museum. The plates on the shoulder and prteoper-culum are as in the young of Ghce-todon
The Annals and magazine of natural history; zoology, botany, and geology . er than in ThoUchthyes ofyounger age; but this is merely in consequence of the greaterdevelopment of the body in the more advanced stage, itsgrowth being much more rapid than that of the head. 2. Not only Chcetodon, but also other Squamipinnate ge-nera appear to have a TIwUchthys-stRgc. With the speci-men of Ch. citrinellus mentioned above, Hr. Godeifroy sentanother fish, represented in the accompanying woodcut, andnow in the British Museum. The plates on the shoulder and prteoper-culum are as in the young of Ghce-todon; but the fish is distinguishedbesides by a remarkably long andcurved horn above each orbit; adeep groove runs along the lowerside of the horn. The numbers ofthe fin-rays are, D. 1| and A. ^.There are between 50 and 60 trans-verse . series of scales on the ,although it is possible that the horn above the orbit is also an excrescence lost in the moremature state of the individual, it yet reminds us of thosespecies of Heniochus which arc provided with more or less. 320 Dr. J. E. Gray on Scapia Phayrei. developed orbital processes. Indeed Ileniochus monoceros and//. varius approach our specimen very closely with regard tothe numbers of the fin-rays. Yet, without further evidence,it would be hazardous to state whether this fish is a youngGlujiodon or lIe,niochus. With regard to Tliolichthys osseus, I have not been able toobtain specimens in a more advanced state of developmentand to determine the genus or species of which it is the young. I have but little doubt that Holacanthus passes also througha Thohchthi/s-i^tEite, and that the pra^opercular spine by whichthis genus is distinguished is the permanent remains of theexpansion of the pracopercular angle, which in other alliedgenera disappears with age. Our acquaintance with instances of fishes undergoing greatchanges in the earlier stages of growth becomes more andmore extended. In many cases the young have been describeda
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