476 FISHES. 



dredged at a depth of 360 fathoms off the coast of West 

 Africa ; the latter genus possesses two gills only. Another 

 genus, covered with large scattered tubercles, Aer/ccooiichthjs, 

 has recently been described from New Zealand. 



Thirteenth Family — Cottid.e. 



Form of the tody olAonrj, siib-cylindrical. Cleft of the 

 moidh lateral. Dciitdion feeble, genercdly in villiform bands. 

 Some bones of the head are armed; anel cc bony stety eonneets 

 the prccojierexdar spine with the infraorbital ring. Two dorsal 

 Jins {rarely one), the spinous being less developed than the soft 

 and than the amd. Ventrcds thoracic, with five or less soft 

 rays. 



The fishes of this family are of small size, bad swimmers, 

 and generally living on the bottom, near the coasts, of almost 

 all the arctic, temperate, and tropical seas. Only a few live 

 in fresh water. They prefer shallow to deep water ; and there 

 is only one instance known of a member of thi^ family living 

 at a great depth, viz. Cottus bathybius from the Japanese sea, 

 which is stated to have been dredged in a depth of 565 

 fathoms. Fossil representatives are few in numl^er : two or 

 three species of Trigla ; others, although having a general 

 resemblance to the genus Cottus, were covered with ctenoid 

 scales, and therefore are referred to a distinct genus, Lepido- 

 ■cottus ; they are from tertiary formations. 



Cottus. — Head broad, depressed, rounded in front ; body sub- 

 cylindrical, compressed posteriorly. Scaleless ; lateral line pre- 

 sent. Pectoral rounded, with some or all the rays simple. Jaws 

 and vomer with villiform teeth ; palatine teeth none. 



The " Bull-heads " or " Miller's Thumbs " are small fishes 

 from the shores and fresh waters of the northern temperate 

 zone. Some forty species are known ; the greater number 



