900 FISHES — PEKCOPSID^. 



Diagnosis. — This is the only fish which combines the adipose fin of the 

 salmon, with the small, rough scales of the perch. 



Habits. — Little is known of the habits of the Trout Perch. It is found 

 in the open lakes and in the small streams. I have seen it taken with 

 hook and line from the wharves at Chicago, and I have found it among 

 schools of minnows in small streams of Northern Wisconsin. One or 

 two specimens have been obtained by Dr. Sloan in the Ohio River. It 

 spawns in spring, and its ova are comparatively large like those of the 

 Trout. They are excluded through an oviduct. 



FAMILY AMBLYOPSID^. THE CAVE-FISHES. 



Body moderately elongate, compressed behind ; head long, depressed ; month rather 

 large, the lower jaw projecting; premaxillaries long, scarcely protractile, forming the 

 entire margin of the upper jaw; ja^ws and palatines with bands of slender, villiform 

 teeth ; branohiostegals about 6 ; gill-rakers very short ; pseudobranchiae concealed ; 

 gill-membranes more or less completely joined to the isthmus ; head nailed, the surface 

 sometimes crossed by papillary ridges; body with small, cycloid scales, irregularly 

 placed; no lateral line; vent jugular, close behind the gill-openings; ventral fins small 

 or wanting; pectorals moderate, inserted higher than in most soft-rayed fishes; dorsal 

 without spine, nearly opposite the anal ; caudal truncate or rounded ; cranium without 

 median crest ; stomach coscsal, with one or two pyloric appendages ; air-bladder present ; 

 ovary single; some, and probably all, of the species are ovoviviparons ; in two of the 

 genera the eyes are very rudimentary and hidden under the skin, and the body is trans- 

 lucent and colorless ; fishes of small size, living in subterranean streams and ditches of 

 the Central and Southern United States ; three genera and four species are " all of the 

 family yet known, but that others will be discovered, and the range of the present 

 known species extended, is very probable. The ditches and small streams of the low- 

 lands of our Southern coast will undoubtedly be found to be the home of numerous in- 

 dividuals, and perhaps of new species and genera, while the Eubterranean streams of 

 the central portion of our country most likely contain other species " (Putnam). 



None of this family have yet been recorded from Ohio, and I am not aware of the ex- 

 istence of any cave Streams in the State in which it is likely that they will be found. 

 I give here a brief account of the characters of the species found in the caves of K'en- 

 tacky and Indiana, as they belong to the general fauna of the Ohio Valley. 



Analysis of Genera of Amblyopsid^, 



o. Eyes rudimentary, concealed under the skin ; body colorless. 



I. Ventrals present, small. ..... Amblyopsis. 



66. Ventrals obsolete. ...... Typhlichthys. 



aa. Byes well developed ; body colored ; no ventrals. . . Chologastbr. 



Genus. AMBLYOPSIS. DeKay. 



AmUyopsis, DeKay, New York Fauna, Fishes, 1842, 187. 

 Type, Amhlyopais spelaus, DeKay. 

 Etymology, ambliis, blunt; opeia, vision. 



