125 

 Family Pleuronectidm. 



Chascanopsetta, Alcock. 



Chascanopsetta, Alcock, Journ. As. Soc. Bengal, Vol. LXIII. pt. 2, 1891, p. 128. 

 Pelecanichthps, Gilbert and Cramer, Proc. U. S. Nat. Mns. XIX. 1896, p. 432. 



Mouth very wide, the maxillary being very much more than half the length 

 of the head. Jaws and teeth equally developed on both sides, each jaw being 

 armed with a single row of long slender depressible teeth. Byes on the left side. 

 The dorsal fin commences near the tip of the snout, its rays, and those of the 

 anal, being simple, slender, and scaleless. Caudal free. Scales minute, mem- 

 branous, hardly imbricate. Lateral line with a strong curve above the pectoral. 

 Gill-openings wide, the gill-membranes united in front. Gill-rakers none. 

 Seven branchiostegals. Pseudobranchise large. 



101. Chascanopsetta lugubris, Alcock. 



Chascanopsetta lugubris, Alcock, Journ. As. Soc. Bengal, Vol. LXIII. pt. 2, 1894, p. 129, pi. vi. fig. 4 : Illus- 

 trations of the Zoology of the Investigator, Fishes, pl. XV. fig. 3. 



B. 7. D. 115. A. 80. C. 16. V. 6. 



Body long, low, tapering, the dorsal profile considerably more convex than 

 the ventral. The greatest height of the body is about one-fourth, and the length 

 of the head about one-fifth of the total, caudal included. 



Mouth-cleft very wide, oblique, with the lower jaw strongly projecting : the 

 maxilla, which is hardly expanded posteriorly, is about three-quarters the length 

 of the head, — reaching nearly to the angle of the j:>roperculum. Each jaw is 

 armed with a single row of sharjD curved teeth of two sizes, the larger fairly 

 regularly alternating with the smaller : those of the lower jaw are very close-set, 

 and are strongly depressible inwards across the floor of the mouth : those of the 

 upper jaw are more distant, not so strongly depressible, and rather smaller. 

 Tongue large, free, with a long styliform point. The rami of the lower jaw are 

 capable of very wide divarication. 



The eyes, which are on the left side, are large (their major diameter being 

 about two-sevenths of the length of the head', close-set (less than a- third of a 

 diameter apart), and nearly equal in front. The snout proper is short — about 

 two-thirds the length of the eye. The nostrils are small pores situated in front 

 of the interorbital space. 



The gill-openings are wide, the gill-membranes being free posteriorly : the 

 gill-arches are extremely weak and slender, the gill-lamina? are delicate, and 

 there are no gill-rakers. 



The body and the post-orbital portion of the head are covered with minute 

 membranous hardly imbricating scales, which are somewhat enlarged along the 



