178 ZOOLOGY. 



12. Polypterus, Gill-membrane one rayed ; fins numerous 

 along the back. 



13. Elops. Head smooth ; edges of the jaws and palate 

 rough, with minute teeth; gill-membrave with thirfjr 

 rays, armed In the middle of the outer side with five 

 tooih-like processes. 



14. Argentina. Argentink. Tee//* in the jaws, and on the 

 tongue ; gill-membrane eight rayed ; vent situated near 

 the tail ; ventral fins composed of many rays. 



15. Atherina. Atherine. ZTpper jaro flattish ; gill-mem-' 



brane six rayed ; a silvery line extending along th» 

 sides. 



16. Mugil. Mullet. Body and gill covers^ covered with 

 large scales ; teeth on the tongue and palate ; above the 

 angles of the mouth a hard callous ; gill-memhrans 

 with six incurvated rays. 



17. Exoccetus. Flying-Fish. Head covered with large 

 scales ; gill-membrane with ten rays ; pectoral fins 

 very large and long. 



18. Polynemus. Head compressed^ covered with scales ; 



sjiotit obtuse, prominent ; gill-membrane five to ten 

 rayed ; pectoral fins with distinct, entire, cirri, 



19. Clupea. HERRixa. Mead covo^ressed -, snout inclining 



