[11] 



FLOUNDERS AND SOLES . 235 



a. Gill openings very small, separate, each reduced to a slight slit below angle of 

 opercle ; right ventral beginning at the chin, confluent with the anal ; 

 pectoral fins wanting or very small ; lateral line present, straight ; eyes 

 small; snout dilated, the dorsal beginning upon it. 

 b. Scales present, ctenoid ; caudal fin somewhat confluent with dorsal. 



c. Left ventral rudimentary, with two rays Apionichthys, 39. 



cc. Left ventral well developed, with five rays Achiropsis, 40. 



bb. Scales none ; caudal fin not confluent with dorsal and anal.-GYMNACHiRUS, 41. 

 aa. Gill openings of moderate extent, confluent below. 

 d. Vertical fins well separated. 



e. Eight ventral fin with extended base, confluent with the anal fin ; verte- 

 brae about 28 ; body ovate in outline, the depth nearly half the length ; 

 pectoral fins rudimentary or wanting ; lateral line straight ; scales well 

 developed, ctenoid, those on the head more or less enlarged, those of the 



blind side of the head with fringes Achirus, 42. 



ee. Right ventral fin with short base, free from the anal ; vertebrae 34 to 50 ; 

 body elliptical or elongate, the depth one-third to two-fifths the length ; 

 lateral line single* on both sides. 

 /. Vertebrae 34 to 40; body oblong; pectoral fins usually small, sometimes 



wanting on the blind side Moxochirus, 43. 



ff. Vertebrae 47 to 50 ; body elongate ; pectoral fins subequal, present on 



both sides Solea, 44. 



dd. Vertical fins fully confluent around the short tail, body oblong ; scales very 

 small, ctenoid ; vertebra' (zebra) ^ + 41 = 49 Brachirus, 45. 



Subfamily VI.-CYNOGLOSSINjE. 



(Soles with the eyes on the left side, not separated by a bony ridge.) 



Body elongate, more or less lanceolate in outline, with the eyes and 

 color on the left side ; eyes small, very close together, with no distinct 

 interorbital ridge between them ; mouth small, twisted toward the blind 

 side; teeth little developed, in villiform bauds; edge of preopercle 

 covered by the scales ; gill openings narrow, the gill membranes adnate 

 to the shoulder girdle above, joined together and free from the isthmus 

 below; pectoral fins wanting (in the adult); ventral fins small, that of 

 the blind side often wanting; vertical fins more or less confluent ; scales 

 ctenoid ; lateral line sometimes wanting, sometimes duplicated. 



a. Ventral fin of eyed side only present, free from the anal; no pectoral fins; no 

 lateral line ; head without fringes .• Symphtjrus, 46. 



Subfamily I.-HIPPOGLOSSINJE. 



Genus I.— ATHERESTHES. 



Atheresthes Jordan & Gilbert, Proc. U. S. Nat. Mus., 1880, 51 (siomias). 

 Type : Platysomatichthys stomias Jordan & Gilbert. 

 The single species which constitutes this genusf is one of the most 



*Two lateral lines on the blind side in the Asiatic genus, Pardachirus. 



t Arrow-shaped canine-teeth are also found in tbe Asiatic genus I'settodes Bennett, 

 a curious group somewhat allied to Atheresthes. In Psettodes, the caudal fin is rounded, 

 the dorsal fin begins on the nape, above middle of tbe cheek, tbe scales are small and 

 ctenoid, and there are no gill-rakers. 



