174 ZOOLOGY. 



28. Gasterosleus. Stickle-Back. Gill-membrane, three or 

 six rayed ; belli/ covered with bony plates : dorsal Jin 

 one, between which and the head, are several sharp 

 spines ; ventral Jins spinous. 



29. Mitllus, Surmullet. Head compressed, sloping, scaly ; 



mouth bearded ; bodi/ covered with large slightly 

 affixed scales, which readily drop oflf; gill-membrane 

 three rayed. 



30. Trigla. Gurnard. Head large, covered with strong 

 bony plates ; nose sloping ; gill-membrane seven rayed ; 

 covers spinous ; three slender appendages placed before 

 the pectoral fins. 



3i. Centorogaster. Head compressed, smooth ; body de- 

 pressed, smooth ; gill-membrane seven rayed; fins 

 spinous; the ventral fins connected bj a membrane^ 

 with four sharp spines^ and six soft rays. 



32. Trachichthys. Head rounded in front ; eyes large ; 

 mouth wide, toothless : gill-membrane eight rayed, the 

 four lowermost of which are rough on the edges ; scales 

 rough, strongly adhering ; abdomen shielded with larg« 

 carinated scales. 



