FISHES 109 



Ci Dorsal spines 6 to 15 in number 4. Percoidei. 



62 Dorsal spines 2 to 8 8. Gohioidci. 



d2 Spinous dorsal with 16 or more spines. 



Ci In California 5. Holconoti. 



62 In Texas 6. Chromidcs. 



C2 Body not uniformly scaled or without scales 7. Loricati. 



be Fins without spines. 



Ci Head symmetrical 9. Anacanthini. 



C2 Head asymmetrical; flatfish 10. Hetcrostomata. 



Suborder i. Hemibranchii. — Gills normal (in Gasterosteidae) , 

 but with the pharyngeals reduced in number; upper jaw formed by the 

 premaxillaries : 5 families of mostly marine fishes, i family with fresh 

 water representatives. 



Family Gasterosteidae. — Sticklebacks. Body elliptical, rather slen- 

 der, compressed; caudal peduncle slender; tail fin small; no true scales 

 present, but body either naked or protected laterally by vertically 

 elongate bony plates; 2 to 15 free spines in front of the dorsal fin; a 

 patch of naked skin between the pectoral fin and the opercle on each 

 side; ventral fins consist of i spine and i or 2 rays and subabdominal in 

 position; middle and sides of belly protected by the pubic bones: 

 5 genera and about 1 2 species in America and Europe, 6 in the United 

 States; small fishes living in fresh waters and arms of the sea, most of 

 which build elaborate nests in which the eggs are deposited and where 

 they and the young are protected by the male; they are savage little 

 fish and very destructive to the eggs and young of larger fishes. 



Key to the Fresh Water Genera of Gasterosteidae in the United States 



ai Free dorsal spines 3 to 5. 



bi Sides protected by bony plates i. Gasterosteus. 



bo Sides naked. 



Ci Free dorsal spines 5 2. Eucalia. 



C2 Free dorsal spines 3 4. Apeltes. 



a2 Free dorsal spines 7 to 11 3. Pygosteus. 



I. Gasterosteus L, Sides of body usually protected by vertically 

 elongated plates; 3 free dorsal spines; pubic bones broad and Kttle 

 divergent, joined on the belly, forming a median ventral plate behind 

 and between the ventral fins; gill membranes joined to the isthmus: 

 several species in America and Europe, 3 in fresh water in America. 



Key to these Species of Gasterosteus 



aj In the eastern States G. hispinosus. 



&z On the Pacific slope. 



bi Body wholly mailed G. cataphractus. 



be Body not wholly mailed G. williamsoni. 



