900 FISHES—PERCOPSID A. 
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. “J have seew it taken with 
hook and line from the wharves at Chicago, and I have found it among 
schools of minnows ia 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 AMBLYOPSIDA. THE CAVE-FISHES. 
Body moderately elongate, compressed behind; head long, depressed; mouth rather 
large, the lower jaw projecting; premaxillaries long, scarcely protractile, forming the 
entire margin of the upper jaw; j1ws and palatines with bands of slender, villiform 
teeth; branchiostegals about 6; gill-rakers very short; pseudobranchie concealed ; 
gill-membranes more or less completely joined to the isthmus; head naked, 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 ccezal, with one or two pyloric appendages ; air-bladder present ; , 
ovary single; some, and probably all, of the species are ovoviviparous; 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 undoubtediy be found to be the home of numerous in- 
dividuals, and perhaps of new species and genera, while the subterranean 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 Ken- 
tucky and Indiana, as they belong to the general fauna of the Ohio Valley. 
ANALYSIS OF GENERA OF AMBLYOPSIDZ, 
a. Eyes rudimentary, concealed under the skin; body colorless. 
b. Ventrals present, small. ‘ : . 6 ; AMBLYOPSIS. 
bb. Voeutrals obsolete. j 5 : . : bse TYPHLICHTHYS. 
aa. Eyes well developed; body colored ; no ventrals. ; ; CHOLOGASTER. 
GENUS. AMBLYOPSIS. DeKay. 
Amblyopsis, DeKay, New York Fauna, Fishes, 1842, 187. 
‘ Type, Amblyopsis speleus, DeKay. 
Etymology, amblus, blunt; opsis, vision. 
