NO. 1484. JAPANESE FLOUNDERS AND SOLES— JORDAN A STARRS. 163 



sides, the gape usually, but not always wide. Eyes and color on the right 

 side in most northern forms, on the left side in others. (Halibut tribe.) 



HiPPOC.LOSSIN.K, II 



aa. Mouth unsymmetrical, the jaws on the eyed side with nearly straight outline, 



the bones on'the blind side strongly curved; teeth chiefly on the blind side. 



h. Eyes and color on the right side (with occasional excejjtions). (Plaice 



tribe) Pleuronectin.e, III 



I. SuT^faiiaiiy r'SE;TTiisr..gEc;. 



TTJRBOT TRIBE. 



Large-Tifiontlied fiounders^ with the ventral finft unsymmetrical. — 

 Mouth ^symmetrical, the dentition nearly equally developed on both 

 sides; g-ape usually wide (narrow in Platophrys., Etropus^ etc.), the 

 maxillary commonly more than \ length of head; lower pharyngeals 

 narrow, each with one or more rows or a narrow band of small, sharp 

 teeth; teeth in jaws acute; eyes not minute; pectorals and ventrals 

 usuall}^ well developed; edge of preopercle free; ventral fins dissimilar 

 in form or in position, that of the left or eyed side inserted on the 

 ridge of the abdomen, its base extended along this ridge, its rays more 

 or less wide apart; caudal tin rounded or subtruncate; no accessory 

 lateral line; anal spine usually weak or obsolete; a pelvic spine some- 

 times developed; vertebrte in moderate or small number, 31 to 45. 

 Bod}^ sinistral. Species chiefly tropical or subtropical in distribution, 

 scantily represented in Japan. 



The Turbots are here placed at the beginning of the flounder series 

 as the most primitive of flounders, though not the most simple in 

 anatomical structure. 



KEY TO GENERA. 



a. Pectoral fin of both sides present; septum of gill-cavity below gill-arches without 

 foramen; a deep emargination near the isthmus; ventral fins free from anal. 

 h. Vomer toothless; ventral fins free from anal; caudal fin subsessile. 

 c. Lateral line with a distinct arch in front; teeth small, uniserial, or biserial. 

 (L Interorbital space more or less broad, deeply concave, at least in the males; 

 form broad ovate; gillrakers short and thick. 

 e. Scales small, ctenoid, adherent, 75 to 100 or more; teeth mostly uniserial; 

 anterior rays of dorsal not elevated; pectoral of left side usually fila- 

 mentous in the male; vertebra? (in P. lunatus) 9+30=39. .Platophri/s, 1 



ee. Scales large, deciduous; anterior dorsal rays not elevated Sea-ops, 2 



dd. Interorbital space narrow, sometimes reduced to a simple ridge; dorsal 

 not elevated in front; scales large, firm; gillrakers slender; teeth in two 

 series ". Engi/pnmpoii, 3 



II. SuTafainily HIPPOGLOSSIISr^^. 

 HALIBUT TRIBE. 



Large-mouthed Jlou7ide7's, with the ventral fn.^ sym metrical.— Mouth 

 symmetrical, the jaws and the dentition nearly equally developed on 

 both sides; gape usually wide, the maxillary more than i length of 

 head; lower pharyngeals narrow, usually with but 1 or 2 rows of sharp 



