814 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



similar, shorter; caudal various, sometimes coalescent with dorsal aud 

 anal; pectorals inserted rather high, sometimes wanting; ventrals 

 under the pectorals, usually of several soft rays, sometimes wanting. 

 Fishes mostly carnivorous, inhabiting sandy bottoms in all seas, some 

 species ascending rivers. Many of them are important food-fishes. 

 Genera about 40 ; species nearly 400. 



(PleuroncctidcK Gunther, iv, 399-504.) 



a. Pectoral and ventral fins both present ; caudal distinct; margin of prcopercle more 



or less free. 

 .6. Mouth large; teeth nearly equally developed on both sides of the mouth. 



c. Ventral iin of the left side inserted nearly on the ridge of the abdomen; body 



sinistral. 

 d, Vonier with teeth ; lateral line arched in front ; scales small or obsolete. 



BOTHUS, 449. 

 dd. Vomer toothless; lateral line not arched; scales well developed, mostly 



ciliated CITHARICIITHYS, 450. 



cc. Ventral fins both lateral; vonier and palatines toothless. 

 e. Caudal fin lunate. 



/. Lateral line arched in front; scales cycloid HiPPOGLOSSUS, 451. 



ff. Lateral line not arched. 



g. Teeth not arrow-shaped; gill-rakers few, short. 



PLATYSOMATICHTHYS, 452. 

 gg. Teeth arrow-shaped; gill-rakers numerous, long. 



ATHERESTHES, 453. 

 ee. Caudal fin not lunate, the middle rays produced. 



h. Lateral line arched in front; body usually sinistral. 



PARALICHTHYS, 454. 

 Mi. Lateral line not arched; body dextral. 



HlPPOGLOSSOIDES, 455. 

 6&. Mouth small; teeth, if present, most developed on the blind side. 



j. Teeth small, acute, in several series: lateral line nearly straight, 

 with an accessory branch ; scales small, cycloid ; 

 eyes dextral. 

 fc. Lips longitudinally plicate; dorsal fin beginning on the blind 



side PLEUKO VICIITII YS, 450. 



kk. Lips simple; dorsal fin beginning on the median line. 



HYPSOPSETTA, 457. 

 jj. Teeth in one series. 



1. Teeth rather largo, bluntish or trenchant; eyes dextral (some- 

 times sinistral in one species); veil trals( usually) both 

 lateral. 

 m. Dorsal fin with less than 80 rays; anal with less than GO. 



Pl.EUROXECTES, 458. 



mm. Dorsal fin with more than 95 rays; anal with more than 80; 



body unusually elongate. 

 n. Left side of skull with strong mucous cavities j nnal spine 



present GLYPTOCKPIIALUS, 459. 



n. Left side of skull without conspicuous mucous cavities; 



anal npine obsolete CYXICOGLOSSUS, 460. 



II. Teeth small, acute, in one, series; lateral line nearly straight, 

 simple; scales thin, ctenoid; eyes sinistral; left vtn- 

 tral on ridge of abdomen ETROPUS, 461. 



