174; ZOOLOGY. 



2S. Gasterosteus. Stickle-Back. Gill-membrane, thice or 

 six rayed ; bell^ covered with bony plates : clonal Jin 

 one, between whicii and the head, are several sharp 

 spines ; ventral Jins spinous. 



29. MuUus. Surmullet, i/earf compressed, sloping, scaly ; 



mouth bearded ; body covered Avith large slightly 

 affixed scales, which readily drop off ; 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 Jins, 



31. Centorogaster. JieatZ compressed, smooth; body de- 

 pressed, smooth; gill-membrane seven rayed; Jms 

 spinous; the ventral Jins connected by a membrane^ 

 with four sharp spines^ and six soft rays. 



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

 7nouth wide, toothless : gill-membrane eight rayed, the 

 four lowermost of which are rough on the edges ; scales 

 rough, strongly adhering ; abdomen shielded with large 

 carinated scales. 



