190 CLASSIFICATION OF PISHES. 



(-B. ornatissimus, fig. 25.), which constitute his order 



26 



PlectognatM: this name^ however, we retain, since, by 

 the anatomical investigations of this eminent naturahst, 

 the true nature of the gills were first made known. 

 The most general characters belonging to this group 

 will now be noticed in the order of their prevalence. 

 In the iirst place, they are universally destitute of 

 true or imbricate scales: the body is soft and naked, 

 as in the Chironectid(F, or frog-fish ; or it is hard and 

 coriaceous : in the Balistidce, or file-fish, the skin is 

 hard, and scored * into diamond-shaped patterns (^fig. 



26.) : when magnified (o), the 

 granulations are distinctly seen, 

 the interstices being smooth. In 

 others, the body is either covered 

 with spines, or incased with 

 bony plates, the sutures of which 

 fit to each other, and do not^ 

 as in ordinary fishes, lay in an 

 imbricate or tile-like manner upon each other. The 

 skeleton is neither strictly osseous, nor cartilaginous, but 

 is a mixture of both structures ; presenting a gradation 

 from the soft and cartilaginous structure to that which 

 is hard and truly osseous : the assertion, therefore, that 

 its '' entire general structure is that of ordinary fishes," 

 is not borne out by fact ; since M. Cuvier himself 

 acknowledges, that, in the majority^ the bones are semi- 



* Scored or reticulated : we use this term to denote the peculiar reticu- 

 lated markings on the shagreened skin of certain Balistidce, which give 

 them, at first, the appearance of possessing diamond.shaped scales. 



mfMfim. 



