94 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY—II. 
Leptops, RAFINESQUE (1820), Ichthyologia Ohiensis, 64. 
Opladelus, RAFINESQUE (1820), Ichthyologia Ohiensis, 64. 
Llictis, RAFINESQUE (1820), Ichthyologia Ohiensis, 66. 
Pylodictis, RAFINESQUE (1820), Ichthyologia Ohiensis, 67. 
Hopladelus, GIL (1862), Proc. Bost. Soc. Nat. Hist. 45, and of most late authors. 
Pelodichthys, GILL & JORDAN, MSS.—JoRDAN (1876), Ann. Lyc. Nat. Hist. N. Y. —. 
Pimelodus sp., KIRTLAND, Cuv. & VAL. et Auct. 
ETYMOLOGY.—7yAoc, nud ; cx6ve, fish. 
Typr.—Pilodictis limosus Raf. = Silurus olivaris Raf. 
Body much elongated, very slender, much depressed, anteriorly 
broader than high. Head large, very wide and depressed, latterly 
expanded, above broadly ovate, and in profile cuneiform. Skin very 
thick, entirely concealing the skull. Supraoccipital bone entirely free 
from the head of the second interspinal. Eyes small. Mouth very 
large, anterior and transverse. The lower jaw always projects beyond 
the upper. Teeth in broad villiform bands on the intermaxiilaries 
and dentaries. The intermaxillary band is convex anteriorly, and pro- 
ceeds to the insertion of the maxillaries, where it is abruptly angularly 
deflected, and proceeds backward as an elongated triangular extension. 
The band at the symphysis is slightly divided and anteriorly separated 
by a small triangular extension of the labial membrane. The lower 
dental is anteriorly semicircular and attenuated to the corners of the 
mouth. There are about twelve branchiostegal rays on each side. 
The dorsal fin is situated over the posterior half of the interval be- 
tween the pectorals and ventrals, and has a spine and about seven 
branched rays. The spine israther small, and more or less enveloped in 
the thick skin. 
The adipose fin is large, and has an elongated base resting over the 
posterior half of the anal; it is very obese and inclines rapidly back- 
ward; itis rather less free posteriorly than in Amiurus. 
The anal fin is small ; it commences far behind the anus, is a little 
-longer than high, and is composed of about thirteen rays. 
The caudal fin is oblong, subtruncated, placed on a vertical basis, 
and with numerous accessory simple rays, recurrent above and beneath 
the caudal peduncle. 
The pectorals have a broad, compressed spine, serrated or dentated 
on its external and internal margins, and with the prolonged fleshy 
integument obliquely striated. 
The ventrals are rounded and have nine rays, one simple and eight 
branched. 
