(aera: pela Saal 
L 
v 
L. Agassiz on the Ichthyological Fauna of Western America. 83 
rays of the dorsal are in fact, enclosed in a continuous membrane, 
the anterior rays only being much longer than those of the mid- 
dle and posterior portion of that fin; occasionally these long rays 
split, and accidentally separate from the following ones, when 
they seem to form two dorsals. 
The character of this genus, as far as the dorsal fin is con- 
cerned, consists in reality vot in its division, but in its great ex- 
tension along the back, and the elongation of its anterior rays. 
The anal is very small in proportion to the size of the fish, and 
inserted far back, so that the length of the abdominal cavity is 
greater than in the genera Carpiodes, Ichthyobus and Bubalich- 
thys, with which Cycleptus is closely allied by the peculiar 
form of its dorsals. Again, Rafinesque remarks that the mouth is 
terminal, round and small. This requires also to be qualified. 
The mouth appears terminal and round only when the jaws are 
protruded to their utmost extent; when closed, it is rather cres- 
ceut-shaped and entirely retracted under the projecting, pointed 
snout; the lips are covered with numerous projecting papillz and 
spread horizontally.—these are moreover continuous around the 
angles of the mouth, so that the upper and lower lips are hardly 
separated by a small fold, and the lower lip is slightly emarginate 
“04 middle, while in other genera of this tribe it is actually 
obed. 
The pharyngeal bones are strong, their anterior surface being 
flattened and their greatest diameter being the transverse one, as 
Ichthyobus, as is also the case in Bubalichthys, and they are 
gradually increasing in size, and relative thickness from the upper 
part of the arch to its symphysis, but they are much fewer and 
farther apart than in the latter genus. ‘Their inner edge Is trans- 
Verse, rather bluut, though the middle ridge is somewhat project- 
ig; the lower teeth are so shaped that their inner angle Is hardly 
higher than the outer, 
while in the middle and 
Upper teeth it is gradu- 
ally more projecting, 
and from the middle of 
the arch upwards forms 
& prominent point arch- 
ed outwards, 
ig. 4, a, represents 
t 
8 
the righ pharyngeal of 
ens 
