FISHES lOI 



A. speleus DeK. Length 125 mm.; head 3; depth 4.5; body color- 

 less, translucent; rays of dorsal fin 9; anal 8: Mammoth Cave, and other 

 subterranean streams in Kentucky and Indiana; common. 



4. Troglichthys Eigenmann. Eyes very rudimentary, concealed 

 beneath the skin; sides with tactile papillae; scleral cartilages present; 

 I pyloric caecum; body colorless: i species. 



T. roscE Eig. Scleral cartilage large, forming a hook over the eye: 

 caves of Missouri. 



5. Typhlichthys Girard. Similar to Amhlyopsis, except that it 

 has no ventral fins: i species. 



T. subterraneus Gir. Length 50 mm.; colorless and translucent; 

 rays of dorsal and anal fins 7 or 8 : subterranean streams and wells from 

 Indiana to Alabama; common. 



Order 8. Salmopercae. — The trout perch. Adipose fin pres- 

 ent; ventral fins abdominal; dorsal, anal and ventral fins each with i or 2 

 spines; maxillary toothless and not forming the margin of the mouth; 

 scales ctenoid; head scaleless; pseudobranchiae present: i family. 



Family Percopsidse. — Body elongate; caudal peduncle long and 

 slender; mouth small, horizontal; branchiostegals 6 ; tail forked ; stomach 

 siphonal with 10 pyloric caeca: 2 genera. 



1. Percopsis Agassiz. Body slender, pellucid; dorsal fin with 2 

 feeble spines; anal with i: i species. 



P. omiscomaycus (Walbaum). Trout perch. Length 150 mm.; 

 head 3.75; depth 4.3; color pale olivaceous, with a silvery stripe along 

 the lateral fine; upper half of body with dark round spots; rays of dorsal 

 fin II, 9; anal I, 7; scales 6-50-7: Delaware and Potomac Rivers to 

 Kansas, and northward to Hudson Bay; common in the Great Lakes. 



2. Columbia Eigenmann. Body rather robust; dorsal and anal fins 

 with 2 strong spines each; posterior margin of preopercle with a few 

 short spines; lateral line imperfect: i species. 



C. transmontana Eig. Length 100 mm.; head 3; depth 3.5; color 

 greenish, upper half of body with large dark spots; rays of dorsal fin II, 

 9; anal II, 6; scales 7 to 9-44 to 46-7 : lagoons along the Columbia River; 

 locally common. 



Order 9. Xenarchi. — Pirate perch. Dorsal fin single, with few 

 spines; ventrals thoracic and with 7 rays and without spines; no adipose 

 fin: I family. 



Family Aphredoderidae. — Body elliptical; caudal peduncle thick; 

 scales ctenoid; sides of head scaly; lateral fine imperfect or wanting; 

 pyloric caeca about 12; anus below the preopercle in the adult but 

 behind the ventral fins in the young; tail fin rounded: i genus. 



