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PLECTOGNATHI. 
ORDER III. PLECTOGNATHI. 
{Fishes 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 
