426 DEEP-SEA FISHES OF THE ATLANTIC BASIN. 



The total length of the specimen is 59 lines, of which the head makes 7, and the head 

 and trunk together 17. 



This species was picked up in mid-ocean in the South Atlantic, and was purchased by 

 the British Museum from the Godeffroy Collection. 



Order HETEROSOMATA. 



Cranium posteriorly normal; anteriorly with twisted vertex, to allow two orbits on tlie 

 same side, or one vertical and one lateral ; basis cranii not quite simple. Dorsal fiu long, 

 of jointed rays. Superior pharyngeals 4, the third longest, much extended forward, the 

 inferior separate. (Cope.) 



Family PLEURONECTIDyE. 



/ Pleronetti, Rafinesqce, lndice <V Ittiologia Siciliana, 1810, 14. 



Pleuronectidw, Fleming, British Animals, 1828, 178. — Bonaparte, Catalogo Metodicodei Pesci Europei, 

 1846, 47.— Swainson, Nat. Hist. Fishes, etc., 1839, II, 187.— Gcnther, Cat. Fish. Brit. Mus., IV, 399.— 

 Giix, Air. Fam. Fish., 1872, 2, (No. 15).— Jordan and Gilbert, Bull, xvi, U. S. Nat. Mus., 813. 



Pleuronecteoidei, Bleeker, Tentamen, 1859. xv. 



Body strongly compressed, more or less oval or rhomboid, and with one of its sides 

 (which is upward when the animal is reclining on its side) colored, and the other (which is 

 downward) generally colorless; the scales are variously developed (sometimes ctenoid, 

 sometimes cycloid, and sometimes wanting) ; the lateral line is continuous behind; the head 

 compressed, more or less rhomboid, and with the snout pointed; both eyes are on the same 

 side, one being on or near the forehead, the other comparatively low down; opercula 

 normal, unarmed, not concealed by skin ; mouth terminal, and with an oblique lateral cjeft and 

 of various extent; branchial apertures continuous below; branchiostegal rays 5 to 8; dorsal 

 elongated, extending generally from about the rostral region to near the caudal fin; anal fin 

 also elongated, and extending about as far back as the dorsal; both arc composed almost 

 solely of articulated rays ; caudal fin distinct from the dorsal and anal; pectorals on both 

 sides; ventrals jugular. The skeleton has numerous vertebra; ; pyloric cseca are generally 

 developed, but in small number. 



KEY TO THE SUBFAMILIES AND DEEP-SEA GENERA OF PLEURONECTIDW. 

 (From Gill & Jordan, modified.) 



I. Mouth small; supramaxillary ending before or under front of eye; teeth largest on blind side. 



Pleuroneclina 

 A. Teeth in one series. 



1. Teeth rather large, bluntish or trenchant: eyes dextral (sometimes sinistra] in one species); 

 ventrals (usually) both lateral. 



a. Dorsal fin with less than 80 rays; anal with less than 60. Eyes dextral. 



Lateral line not arched. Scales not imbricated, usually ctenoid in male, cycloid in female. 



Pleuronectes 

 Lateral line arched anteriorly. Scales ctenoid Limanpa 



b. Dorsal fin with more than 95 rays; anal with more than 80; body unusually elongate. 



Left side of skull with strong mucous cavities. Lateral line nearly straight. Anal spine 

 present. Eyes dextral Glyptocepiialus 



Mucous cavities not present. Caudal subsessile; left pectoral only present; lateral Hue 

 present, arched on eyed side, straight on blind side. Eyes sinistral. 



Monolenf. 



II. Mouth large, supra maxillaries end under eye; ventrals lateral ; vomer and palatines toothless. 



Hippoglossinw 



A. Caudal fin lunate. 



1. Lateral line arched in front; scales cycloid Hippoglossus 



2. Lateral line not arched. 



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



B. Cauda] fin not lunate, the middle rays produced. 



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



a. Dorsal fin single PARALlcnTms 



b, Dorsal in two parts, its anterior rays, as well as sinistral ventral, much prolonged. Scales 



ctenoid Notosema 



2. Lateral line not arched. Body dextral HippoGlossoides 



