510 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
separate; no air-bladder; preopercle with its margin usually distinct, not wholly adnate or hidden by 
the skin of the head; vent not far behind head, the viscera confined to the anterior part of the body. 
Scales various, rarely absent, usually small. Lateral line usually present, extending on the caudal 
fin, sometimes duplicated or wanting. Dorsal fin long, continuous, of soft rays only, beginning on the 
head; anal similar, shorter; caudal various, sometimes coalescent with dorsal and anal; pectorals 
inserted rather high, rarely wanting; ventrals under the pectorals, usually of several soft rays, one of 
them sometimes wanting. Fishes mostly carni verous, inhabiting sandy bottoms in all seas, some species 
ascending rivers. Many of them are important food fishes. Genera about 55; species nearly 500. 
a. Mandibular membranes forming a gular pouch Pelecanichthys, p. 510 
aa. Mandibular membranes not forming a gular pouch. 
b. Scales small, 80 to 140. 
c. Scales about 140; maxillary more than one-half head Chascanopsetta, p. 511 
cc. Scales 80 to 100; maxillary about one-third length of head. 
d. Teeth in each jaw in narrow villiform bands; origin of dorsal over middle of eye Pcecilopsetta, p. 512 
dd. Teeth in jaws not in villiform bands; origin of dorsal not over middle of eye. 
e. Interorbital broad and concave; dorsal 92; A. 69; caudal convex Platophrys, p. 512 
ee. Interorbital narrower; dorsal 112; anal 91; caudal not convex Anticitharus, p. 514 
bb. Scales large, 36 to 46 Engyprosopon, p. 514 
Genus 257. PELECANICHTHYS Gilbert & Cramer. 
Eyes and color on the left side; mouth symmetrical, of enormous extent, gape about as long as 
head; mandible, extending anteriorly far beyond tip of snout, the projecting portion decurved and 
falciform, the rami very slender and flexible, each rotating inward, so that the teeth of the 2 rami 
meet and interlock in the closed mouth, instead of being opposed to those of the upper jaw; mandi- 
bular membranes voluminous, forming a veritable gular pouch and permitting wide divarication of 
the mandibular rami, which can be also closely apposed for their entire length. The posterior angle 
forms a slender process, projecting beyond the mandibular articulation and extending behind the 
posterior margin of the opercle; premaxillary, maxillary, and palatopterygoid formed of .'i very slender 
bony rods, parallel and closely juxtaposed for the greater part of their length; branchiostegals 7; 
gillrakers absent; preopercular margin free; dorsal and anal fins very long, the former commencing 
on the snout; caudal peduncle extremely short, a low fin-fold joining dorsal and anal with rudimentary 
caudal rays; caudal lanceolate; ventrals unsymmetrical, the left slightly more anteriorly placed, 
inserted on the ridge of the abdomen, its membrane leading to base of first anal ray; vent displaced 
well to the right side of the ridge slightly in advance of front of anal, a small papilla (genital papilla?) 
occupying a corresponding position to the left of the ridge; scales excessively fine; lateral line single, 
conspicuous, continued on to the caudal fin; with a short, low anterior arch. 
Pelecanichthys Gilbert & Cramer, Proc. U. S. Nat. Mas., XIX, 1897 (Feb. 5), 432 ( erumenalis ). 
426. Pelecanichthys erumenalis Gilbert & Cramer. Fig. 226. 
Head (horizontal length) 4.3 to 4.5 (5.25 in smallest specimen ) ; depth 3.5 to 3.6 (4 in smallest); 
D. 121; A. 88; P. 13 or 14; V. of both sides with 6 rays; about 230 to 240 pores in the course of the 
lateral line. 
Body slender, excessively compressed, tapering slowly and uniformly toward tail, the 2 outlines 
very weakly arched for the greater part of their extent. Anterior outline of head strongly decurved, 
the physiognomy resembling that of Glyptocepluilus. Bases of dorsal and anal tins wide, translucent, 
sharply marked off from rest of body, constituting together half the greatest depth of body. Abdomen 
very short. 
Head very obliquely placed, the eyes closly approximated near the upper anterior profile, the 
cheeks narrow, oblique, upper limb of preopercle nearly horizontal, lower limb nearly vertical; 
mandible extending beyond premaxillaries for over one-fourth its length; rami so articulated as to 
permit a slight inward and outward rotation on their long axes, in addition to other movements; gular 
membrane large and loose, falling into folds when the jaws are closed; the entire mechanism of the 
lower jaw seems adapted to seizing food between the rami, and forcing it down between and below 
them. Teeth in both jaws in a somewhat uneven single series, those in mandible largest, smaller teeth 
