Jordan avd Evcrmann. — Fishes of North Avicrica. 2005 



It will probably appear to some that the process of generic subdivision 

 has been in this paper carried too far. It is possible that this is true, but 

 the arrangement which we have adopted seems to bring out the relations 

 of the different forms better than can bo done by a more conservative view 

 of the genera. (PleuronectidWf Giinther, Cat., iv, 1862.) 



Subfamilies of Pleuronectid^. 



A. Ventral fins symmetrical, similar in position and in form of base, the ventral of the 



colored side not extended along the ridge of the abdomen. 



a. Mouth nearly symmetrical, the dentition nearly equally developed on both sides, 



the gape usually but not always wide. (Halibut tribe.) Hippoglgssin.i!, i. 



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. 



6. Eyes and color on the right side (with occasional exceptions). (Flounder 



tribe.) Pi.EURONECTINiE, II. 



AA. Ventral fins unsymmetrical, dissimilar in position and usually also in form, the 

 ventral fin of the eyed side being extended along the ridge of the abdomen. 

 Eyes and color on the left side. (Turbot tribe.) Psbtti.\.e, in. 



Analysis of Genera, 

 i. hippoglossin^. 



(Halibt't Tribe.) 



Largc-mouthrd ilonndrrs with the mitral fins symmetrical. — Mouth sym- 

 metrical, the jaws and the dentition nearly equally developed on both 

 sides; gapo usually wide, the maxillary more than i length of head. 

 Lower pharyngeals narrow, usually with but 1 or 2 rows of sharp teeth; 

 teeth in jaws usually acute. Eye8 largo; edge of preopercle free. Pec- 

 toral and ventral fins well developed, the vevtral fins similar in posilion and 

 in form of base, the ventral fin of the eyed side not being attached along 

 the ridge of the abdomen. Septum of gill cavity without foramen. 



a. Vertebra? and fin rays much increased in number (the vertebra? about 50 ; dorsal raya 

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

 lateral lino simple; anal spine mostly obsolete. Dextral species, arctic in dis- 

 tribution. (Genera allied to Hippoglosgus.) 

 h. Large teeth in both jaws arrow-shaped, biserial, some of them depressible; 

 upper eye with vertical range; gill rakers short; scales deciduous, ciliated; 

 lateral line without arch; flesh soft. Vertebra? (in A. stomias) 12 + 37 = 49. 



Atheresthes, 1013. 

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

 cycloid; gill rakers long and slender; eyes strictly lateral, 

 c. Lateral line without anterior arch; lower pharyngeal teeth uniserial. 



Reinhardtius, lOM. 



ec. Lateral lino with an anterior arch; lower pharyngeal teeth biserial; ver- 



tebr.Ti (in R. hvppoglossus) 16 + 3-1 = 50. Hippoglossus, 1015. 



aa. Vertebriie and fin rays in moderate number (vertebra? less than 46; dorsal laya 



fewer than 95 ; anal rays fewer than 75) ; caudal fin double truncate or rounded, 



the median rays longest. 



d. Lateral lino without distinct anterior arch; vertebra? 40 to 46; body normally 



dextral;" caudal peduncle distinct; scales ciliated; anal spine usually 



strong. Species of subarctic distribution. (Genera allied to IIipi)o<jlos- 



soides.) 



* Frequently sinistral in Hippoglossoides elassodon. 



