164 I'lloVKEDlXaS OF TIIK NATIONAL MUSEUM. vol. xxxi. 



teeth; teeth in jaws usually acute; eyes large; edge of preopercle free; 

 pectoral and ventral tins well developed, the ventral fins similar in posi- 

 tion and in form of l)ase, the ventral fin of the eyed side not being 

 attached along the ridge of the abdomen. Septum of gill cavity with- 

 out foramen. 



The existing species are mostly arctic or subarctic, and mostly dex- 

 tral, ))ut the more primitive forms (allied to PandicJitJiyx) are largely 

 semitropical and sinistral. 



KEY TO GENERA. 



a. Vertebra^ and fin rays in moderate nund)ers (vertebrae fewer than 46, dorsal rays 

 fewer than 95, anal rays fewer than 75) ; caudal fin not concave, the middle rays 

 longest. 

 h. Dorsal fin beginning in advance of eye; teeth sharp, uniserial; eyes sinistral 

 (rarely reversed) ; lateral line with a strong arch in front; no anal spine. 

 Species tropical or semitropical, allied to Paraliddliys. 

 c. Scales moderately ctenoid; gillrakers slender; some of the teetli canine-like; 

 noni' of the rays much produced; vertebn^e .30 to 40. 

 d. Lateral line with a short accessory branch extending from near the opercu- 

 lar angle to base of dorsal fin ; l)ody rather deep Psrndorli<»i)bvs, 4 



(/(/. Lateral line without accessory liranch; body more elongate; mouth large. 



J'ardlirlilln/s, 5 

 hh. Dorsal (in beginning above the pupil. 



e. Lateral line with short more or less semicircular arch in front; vertebra' .35 to 

 41; anal spine present or absent; body normally sinistral; scales ctenoid; 

 teeth rather small (genera allied to Veraspcr, in the temperate Pacific). 

 /. Anal spine weak or obsolete; teeth in two series. 



g. Gillrakers long and slender Ni/striuK, 6 



gr/. Gillrakers short and broad ]'er(it<per, 7 



//'. Anal spine strong; teeth uniserial; interorbital area scaly. .J(v//*^//oy«e//a, 8 

 ee. Lateral line without distinct arch in front; vertebra 40 to 46; body normallj'^ 

 dextral; scales ctenoid; anal spine usually present. Species of subarctic dis- 

 tril)ution, allied to Hlppoglossokles. 

 It. Lateral line simple, without accessory branch; teeth sharp, uniserial below. 

 ('. Upper eye lateral; no bony or wartj^ plates. 

 j. Jaws with distinct canines; lateral line descending in a long curve. 



( 'i/iiopseftd, 9 

 jj. Jaws with subequal teeth; lateral line nearly straight. 



X. Scales small, chiefly ctenoid; flesh firm; gillrakers rather few, 10 to 15 

 below angle; teeth uniserial in both jaws; vertel)ra 45. 



III])j)0(jlus.<iul<1('i<, 10 

 XX. Scales mostly cycloid; flesh feeble; gillrakers rather numerous, 



about 25 below angle Cleistlienpx, 1 1 



ii. Upper eye nearly vertical, on the midcUe line of upper outline of body, 

 as in Atheredhea, the dorsal beginning behind it; head with warty 



plates Protopsetta, 12 



an. Vertebra and fin rays much increased in number (the vertebra^ about 50; dor- 

 sal rays about 100, anal rays about 85); body comparatively elongate; caudal 

 fin lunate; lateral line simple; and spine mostly obsolete. Dextral species, 

 arc;tic in distribution, ((jenera allied to Illppoylon^ns.) 

 y. Large teeth not arrow-shaped, biserial above, uniserial below; scales very 

 small, cycloid; gillrakers long and slender; eyes strictly lateral. 



