^84 PLECTOGNATHI. 



ORDER III. PLECTOGNATHI. 



(FisJies with soldered jaws.) 



The skeleton in this Order is partly bony in 

 texture, and partly cartilaginous, presenting a 

 decided approach to the following group, in 

 which the gristly structure wholly prevails. The 

 ribs are present only as mere vestiges : the jaws 

 are formed by the union (or soldering together, 

 if we may so speak,) of the maxillary and inter- 

 maxillary bones, and the arch of the palate is 

 united to the skull, so as to be deprived of in- 

 dependent motion. Hence the mouth in these 

 fishes is small, powerless, and almost motionless. 

 The gill-covers and gill-rays are imperfectly de- 

 veloped ; and are concealed under the thick skin, 

 leaving only a small orifice for the escape of the 

 water from the gills. The body is destitute of 

 true scales ; the skin is either hard and leathery, 

 and scored into lozenge-shaped divisions, or 

 covered with hard bony spines, or soft and 

 mucous. The form is usually short and thick, 

 sometimes quite destitute of the proportions that 

 we are accustomed to see in other fishes, and, 

 as it were, deformed: the fins are commonly 

 small, and often remarkable for their position 

 or structure ; there are no proper ventrals. 



The Order before us is very limited in extent 

 as compared with the others ; the fishes which 

 compose it, though presenting some curious 



