THE COBITIDiE, OR LOACHES. 363 



through a horizontally elongated aperture that exists on 

 the outer side of each, — these bones are analogous to 

 the scapulae : to their outer surfaces the bones of the 

 proximal extremity of the pectoral fins are articulated ; 

 and the fin, being moved by powerful muscles, produces 

 that rapidity of motion observable in this little fish." 

 Another peculiarity, existing in the upper surface of the 

 head, is the want of union in the two parietal bones at 

 the top, — a deficiency which has been noticed by the late 

 celebrated naturalist, Guilding, to occur in the Iguana 

 tuberculata, or common guana of the West Indies. 

 " This peculiarity in the loach," observes Mr. Yarrell, 

 " is another instance of a relation in structure between 

 the fishes and reptiles."* How far these peculiarities of 

 the true loaches extend to the genus Anableps, and the 

 other groups, is entirely unknown. 



(293.) The natural arrangement of this family, from 

 the paucity of forms yet known to belong to it, can- 

 not, as yet, be attempted. We must therefore rest sa- 

 tisfied with taking a hasty glance at those few genera 

 which, from their affinity to the typical Cobitince, or by 

 being known to be viviparous, appear to form broken 

 links in that chain of affinity which unites the loaches 

 to the carps. 



(294-.) The extraordinary genus Anableps, or the 

 double-eyed loach, is probably one of the typical ex- 

 amples. It was separated from the genus Cobites by Ar- 

 tedi t, and Gronovius has given three admirable figures of 

 it in his valuable work.J Its body is cylindrical, covered 

 by hard scales, and having the mouth furnished with 

 numerous small teeth, while others, small and globular, 

 are placed on the pharyngeal bones. It is chiefly re- 

 markable, however, for its eyes, which are large, very 

 prominent, and placed close to the snout; the frontal 



* Brit. Fishes, vol. i. p. 380. We may also add, that this is likewise 

 another evidence of the original union of the three aberrant circles of the 

 Vertebrata into one great circle, as conjectured by us some years ago ; so 

 that the classes Pisces, Reptilia, and Amphibia would form a circle, were 

 there not so many forms extinct among the saurian reptiles. 



t Not, as'Cuvier intimates, by Bloch. 



I See Gronov. Zoophy. pL 1. fig. 1 — 3. 



