FISHES 31 



laterals 26 to 30; ventrals 7 to 10; rays of dorsal fin 35; anal 28: Pacific 

 Ocean from San Francisco northwards, ascending the streams; not used 

 for food. 



2. Scaphirhynchus Meckel. Snout broad and shovel-shaped; spir- 

 acles absent; caudal peduncle slender, long and flattened, and covered 

 with bony plates; pseudobranchiae absent; tail ending in a long filament; 

 ribs 10 or 11: i species. 



S. platorynchus (Rafinesque). Shovel-nosed sturgeon. Length 

 1,200 mm.; head 4; depth 8; weight 9 lbs.; color pale olive; dorsal plates 

 17 or 18; laterals 41 to 46; ventrals 11 to 13; rays of dorsal fin 32; anal 

 20: upper and middle Mississippi Valley; common. 



3. Parascaphirhynchus Forbes and Richardson. Like Scap/ii- 

 rhyncJius but with the belly naked; ribs 20 or 21: i species. 



P. alhus F. and R. White sturgeon. Length 1,000 mm.; weight 

 5 lbs.; color very light gray or white; dorsal plates 16 to 19; laterals 

 41 to 47; ventrals 10 to 13; rays of dorsal fin 35 to 43; anal 20 to it,: 

 Mississippi and Missouri Rivers; rare. 



Order 2. Holostei. — The bony ganoids. Skeleton bony; branch- 

 iostegals present; mouth terminal and with teeth; body covered with 

 ganoid or cycloid scales; tail heterocercal; air bladder cellular and lung- 

 like and connected by a sort of glottis with the oesophagus: 2 suborders, 

 with 5 American species. 



Key to These Suborders 



ai Scales ganoid i. Ginglyniodi (p. 31). 



a2 Scales cycloid 2. Halecomorphi (p. 7,2)- 



Suborder i. Ginglymodi. — Scales ganoid, rhombic in shape; 

 vertebrae opisthoccelous: i family. 



Family Lepisosteidae. — The garpikes. Body elongate and sub- 

 cylindrical, with rhombic ganoid scales; jaws elongate, forming a 

 long slender snout, the upper jaw of which is composed mostly of 

 the premaxillaries; opercle supporting an acessory gill; branchiostegals 

 3; spiracles absent; spiral valve rudimentary; rays of both dorsal and 

 anal fins 8: 3 genera. 



Key to These Genera 



ai Snout more than twice the length of the rest of the head i. Lepisosteus. 



a2 Snout not longer than the rest of the head. 



bi Large teeth in upper jaw in a single row 2. Cylindrosteus. 



b2 Large teeth in upper jaw in 2 rows on each side 3. Atractostens. 



