36 
MONOGRAPH OF THE FRESH WATER 
III. 
COTTK 
Origin of anal fin opposite to third ray of 
second dorsal. Pectorals shorter than 
the head. Vent placed midway between 
snout and tip of caudal fin. 
. RICHARDSONII. 
Origin of anal fin opposite to sixth ray of 
second dorsal. Pectorals of same length 
as head. Vent nearer to snout than 
Body fusiform, to base of caudal fin. 
» COGNATUS. 
elongated. Upper rays of pectorals branched; their tip 
extending to anterior margin of second 
dorsal. Insertion of ventrals in advance 
of first dorsal. 
. WILSONII. 
First dorsal very low. Tip of pectorals ex- 
tending beyond the anterior margin of 
anal. Insertion of ventrals opposite to 
With five rays the first ray of anterior dorsal. 
. BAIRDII. 
Origin of anal opposite to third ray of 
second dorsal. ‘Tip of pectorals extend- 
ing beyond the anterior margin of the 
second dorsal and anal. Insertion of 
ventrals near the lower edge of pectorals 
to ventral fins. A second very minute preopercular spine. 
Body stout | in advance of anterior dorsal fin. 
. ALVORDII. 
preopereular spines. Origin of anal op- 
posite to fourth ray of second dorsal. 
Tip of pectorals not reaching the anal fin. 
Insertion of ventrals even with the lower 
edge of pectorals in advance of the first 
plore: second and third, exceedingly minute, 
dorsal fin. 
. MERIDIONATIS. 
Base of pectorals crescentic; their tip ex- 
tending beyond the fifth ray of second 
dorsal and third of anal fins. Insertion 
of ventrals in advance of the anterior 
dorsal, near the lower edge of pectorals. 
» BOLEOIDES. 
A second minute preopercular spine. ‘Tip 
: of pectorals not reaching the anterior 
Body fusiform/ margin of second dorsal. Base of pec- 
by a free space. 
. FORMOSUS. 
Base of pectorals crescentic; their tip ex- 
tending beyond the fourth ray of second 
dorsal and first of anal fin. Insertion of 
ventrals under ‘the pectorals and in ad- 
vance of anterior dorsal. 
. GRACILIS. 
Base of pectorals slightly curved; their tip 
not reaching the anterior margin of second 
dorsal. Insertion of ventrals in advance 
of anterior dorsal and under the middle 
of pectorals. 
With four 
rays only to( 
ventral fins. | 
. FRANKLINII. 
[Body cylindri- 
cal, or subcy- 
lindrical and 
Base of pectorals crescentic; their tip not 
reaching the anal fin. Insertion of ven- 
trals under the upper edge of pectorals. 
. GOBIOIDES. 
stout. Base of pectorals straight; their tip not 
reaching the anterior margin of anal. 
Insertion of ventrals behind the base of 
pectorals, and in advance of the anterior 
dorsal. 
«+ VISCOSUS. 
Head subtuberculous; region behind the 
eyes and lateral line, rough. 
and slender. | torals crescentic. Dorsal fins separated 
. FABRICII. 
