On the natural history and classification of fishes, amphibians, and reptiles / by William Swainson.

  • William Swainson
Date:
1838-1839
Catalogue details

Licence: Public Domain Mark

Credit: On the natural history and classification of fishes, amphibians, and reptiles / by William Swainson. Source: Wellcome Collection.

    350/386 page 338
    S38 (279‘) We are thus brought back again to the point from whence we started ; and we find that the genera of the LoricaricB describe a circle^ whose analogies may be thus expressed: — Genera of the Loricarin^. Analogies. Sub-families of the SiLURiD^. Lmlcaria. Hymloma- P™elodin*. Hc^ltaoma. ] *“ ] Silurin*. Cataphractus. Eyes very small, nearly vertical. Aspredin^. Sturisoma. Snout lengthened, depressed. Sorubinje. The representation wliich these genera of the Lo-- ricarincB gives us of the primary divisions of the whole family, developes their analogy, likewise, with the primary orders of fishes. It is, indeed, a most in- teresting circumstance to find that in such a group as this we should have a representation of the Gymnetes, or riband-fish, in the compressed shape of Hoplisoma^ so totally at variance with all the other genera; while the small vertical eyes, and the general aspect of Cata- phractus, remind us immediately of Aspredo. (280.) The sub-family of the Pimelodin^ is dis- tinguished by positive and negative characters, or, rather, of two which are universal, and of two which admit of some partial exceptions. The mouth, in the first place, is always terminal: the body, likewise, is naked; for although, in consequence of their close affinity to the Loricarince, some few of these fishes have a single row of small plates upon their sides, and even on their head, yet these plates never extend beyond the nape. They have all two dorsal fins; the hinder being completely adipose, or without any vestige of rays. Their more striking peculiarity, as already remarked, is in the length of the belly and tail being equal, so that the anal fin is never of that exceeding length which it is in all the SilurincB, Some idea of the numerous modifications of form that enter into this group, may he gathered by looking to the contents
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