364 



CLASSIFICATION OF FISHES. 



bone forms a projecting ledge over them : the cornea 

 and the iris are divided into two portions by transverse 

 bands ; so that, by having two pupils, the eyes appear to 

 be double. Nevertheless, as Lacepede truly observes, 

 there is but one chrystalline, one vitrea, and one retina — 

 a structure, however, of which there is no other ex- 

 ample among vertebrated animals. The organs of ge- 

 neration and the bladder of the male, as M. Cuvier 

 remarks, "have their excretory canal in the anterior edge 

 of the anal fin, which is thick, long, and clothed with 

 scales ; its extremity is pierced, and doubtless serves 

 the purposes of coition." The female is not only vi- 

 viparous, but produces the young in rather an " ad- 

 vanced stage of organisation." Only one species of this 

 singular genus is yet known. 



(295.) We have already given a general account of 

 the loaches, all of which are left under one genus by 

 Cuvier, We have, however, in consequence of the 

 recent investigation of some Indian species, detected two 

 principal groups and several minor variations, which 

 constitute sub-generic distinctions, and have arranged the 

 whole under a sub-family. The genus Cobites is dis- 

 tinguished by having no armature on the head ; those 

 with a broad, rounded tail-fin seem peculiar to Europe, 

 while such as have this fin lobed or forked have hitherto 

 been found only in India. The genus Canthophrys, as 

 its name implies, has a hard spiny process, with one 

 or more points, placed immediately beneath the eye, 

 where, in a state of inaction, it reposes in a groove. Of 

 these, which comprise three sub-genera, chiefly Indian, 

 many are elegantly striped. Dr. Hamilton observes that 

 they are more beautiful fishes than the ordinary loaches, 

 which they but slightly resemble in their appearance, 

 and differ from them still more in their habits, " espe- 

 cially in swimming higher, and in not remaining so 

 stationary at the bottom." The fishes of this sub-genus 

 are much compressed, and -at first sight have a strong 

 resemblance to some of the blennies ; these two groups, 

 in short, appear mutually to represent each other. 



