ee ee ee 
‘ 
SSeS Le re ee, 
FORK-TAILED CHANNEL CAT. 785 
. Head conical in profile, compressed, and with the sides sloping downward and out- 
ward. The supraoccipital bone is prolonged backward, and its emarginated apex re- 
- ceives the acuminate anterior point of the second interspinal. The skull is covered by 
a thin tense skin, through which the sculpture of the bones is apparent; eyes large 
and almost entirely lateral; mouth small, transverse, and terminal; the upper jaw 
protrudes beyond the lower ; teeth subulate and aggregated into a short, laterally trun- 
cated band on each jaw. Branchiostegal rays 8 or 9; dorsal fin situated over the inter- 
val between the pectoral and ventral fins, higher than long, with one long spine and 
usually six articulated rays; adipose fin pedunculated over the posterior portion of the 
anal; anal fin long, and provided with from 25 to 35 rays; it commences near the anus; 
ventral fins each with one simple and seven branched rays; pectoral fins each with a 
stout spine, retrorse-serrate within, and about nine branched rays, The serre of the 
pectoral spines vary with age and circumstances, and do not in this genus give good 
specific characters. Caudal fin elongated and deeply forked, with the lobes equal and 
pointed. 
The genus Jchthelurus is at once recognized by the forked caudal fin, its silvery or 
olivaceous colors, and by its compressed, elongated, and slender body which gives to it 
a peculiarly graceful appearance, very unlike that of the stout, obese and large-headed 
Amiuri. The head is smaller in proportion than in Amiwrus, more compressed, and not 
covered by so thick a skin; the mouth is proportionally much smaller. But the only 
invariable generic distinction resides in the mode of insertion of the supraoccipital or 
interparietal bone into the head of the second interspinal. A firm and immovable 
bridge is thus formed, which gives an uninterrupted passage from the dorsal fin to the 
snout. The silvery coloration is also a marked distinguishing feature. 
It is not generally true that the species of Ichihelurus reach a larger size than those 
of the other genera. Amiurus nigricans and Pelodichthys olivaris far exceed in size any of 
the species of Jchthelurus. 
12. IcHTH@LURUS FURCATUS (Cuv. and Val.) Gill. 
Fork-tailed Chammel Cat. 
Pimelodus furcatus, Cuv. and VAL. (1840), Hist. Nat. des Poiss., xv, 136. 
Ichthalurus furcatus, GILL (1861), Proc. Bost. Soc. Nat. Hist., 43. 
Amiurus furcatus, GUNTHER (1864), Cat. Fish. Brit. Mus., v, 103. 
Ichthelurus furcatus, JORDAN, Bull, U. S. Nat. Mus., x, 75; Man. Vert., Ed. 2d, 1878, 328. 
Pimelodus afinis, BAIRD and GIRARD (1854), Proc. Ac, Nat. Sci., Phila., 26.—Grrarp (1859), 
U. S. Mex. Bound., Ich., 32. 
Description.—Body very slender; head slender, the eye small, wholly anterior, its pos- 
terior margin being in front of the middle of the head; slope from snout to dorsal fin 
more or less concave; skin thin; coloration brightly silvery; anal fin extremely long, 
with 32 to 34 rays ;* its base forming one-third of the length of the body and head ; 
head 44 in length; depth, 4 in adult, 64 in young; pectoral spine 14 in head; length 1 
to 2 feet. 
Habitat, Ohio Valley to Texas, in the larger streams; not common. 
ca IR NE AR NE see I EE Pe BG 
“In this family the rudimentary rays at the beginning of the anal are always in- 
cluded in the enumeration. 
50 
