18 THE FISHES OF OHIO. 
DD. Dorsal fin not asin D. 
P. Dorsal‘fin single, preceded by free spines ; body scaleless.— 
GASTEROSTEID2., 
PP. Dorsal fins, two; the first small, composed entirely of spines; body very 
slender, covered with scales.— ATHERINID&. 
II. VENTRAL FINS PRESENT—THORACIC OR SUB-JUGULAR. 
A. Body covered with scales. 
B. Rays of the ventral fins, I, 5. 
Cy Lateral line extending on caudal fin to tip of middle rays.—SCIAENID&. 
CC. Lateral line not extending beyond base of caudal fin. 
D.  Pseudobranchie or false gills on under side of opercles well devel- 
oped ; head scaled forward to between nostrils.—SERRANID&. 
DD. Pseudobranchiz wanting or covered by skin. 
E. Anal spines, 3 to 10; body more or less deep and compressed.— 
CENTRARCHID2. 
EE. Anal spines, 1 or 2; body usually elongate.— PERCID 2. 
BB. Rays of the ventral fins not I, 5. 
EY Dorsal fin single, with 3 or 4 spines.— APHREDODERID. 
FF. Dorsal fin divided into 2 distinct parts, spines wanting.— GADID. 
AA. Body naked ; dorsal fin with 6 or 7 spines.— CoTTID#. 
III. VENTRAL FINS ENTIRELY WANTING. 
A. Body long and snake-like ; skin cov red with lonz imbedded scales at right angles 
to each other ; lower jaw projecting. — ANGUILLID. 
Series: GANOIDEI. 
CHONDROGANOIDEA (THE CARTILAGINOUS GANOIDS). 
Order: SELACHOSTOMI. 
family: POLYODONTID Al. 
Genus: POLYODON. 
Polyodon spathula (Walbaum). PADDLLE-FISH ; SPOON-BILL, Ca’. 
A very peculiar looking fish, recognizable at once by its long, paddle- 
shaped snout, which is about 4% the length of the body and is thin and flexi- 
ble. The eyes are small and placed near the base of the snout ; opercular 
flap long, reaching back as far as to the ventral fins. Caudal fin large, 
forked, the lobes about equal. Color olivaceous, paler below. This singular 
fish attains a length of 5 or 6 feet, but is of little or no economic importance. 
Taken in the Ohio and Muskingum rivers, Kirtland; ‘‘ one 
was taken in a pound net (in Lake Erie) near Vermillion in 
1874,’’ McCormick; ‘‘common in the Ohio river,’’ Henshall, 
1888. 
