PLEURONECTIN^ 369 



edge, not enlarged anteriorly, uniserial in both jaws ; vomer toothless. Gill-rakers 

 rather short, stout, few in number ; lower pharyngeals of moderate width or rather 

 broad, their width 2 to 4J in the length, generally massive, approximated for at least 

 5 their length, their inner edges more or less angular ; teeth coarse, obtusely conical, 

 rounded or molariform, arranged in two or more rows. Dorsal fin with less than 

 70 rays ; commencing just behind posterior nostril of blind side and above eye ; 

 all the rays simple, many of them scaled, at least on ocular side. Tip of first inter- 

 haemal spine projecting in front of anal fin, which has less than 50 rays. Pectoral 

 fin of ocular side a little larger than that of bhnd side ; middle rays branched. Pelvic 

 fins short-based, subequal and subsymmetrical. Caudal fin with 12 or 13 branched 

 rays, middle rays longest ; caudal peduncle short or of moderate length. Scales 

 small, adherent, more or less imbricated posteriorly, generally embedded anteriorly, 

 ctenoid or cycloid ; the male with rougher scales than the female ; no supplementary 

 scales. Lateral line nearly straight or with a low curve above the pectoral fin ; a 

 .supratemporal branch, without posterior prolongation. Vent median, between 

 the pelvic fins ; intestine not narrow, of moderate length, with 3 or 4 simple coils, 

 nearly entirely contained within body-cavity of blind side ; 2 very short pyloric 

 appendages. Vertebrae (38) 40 (13 -f- 27). 



Four species from Arctic and subarctic seas. 



Synopsis of the Species. 

 I. Lateral line with low but distinct curve above pectoral fin ; lower pharyngeals 

 rather narrow, width 3J to 4^ in length, not very massive, each with 

 2 rows of obtusely conical teeth ; dorsal 59-67, anal 44-49 [Gareus] i. obsciira. 

 n. Lateral line straight or with very slight curve above pectoral fin ; lower 

 pharyngeals broad, width 2 to 3 in length, massive, each with more than 2 

 rows of rounded or molarifrom teeth ; dorsal48-59, anal 35-42 [Liopsetta]. 



A. Head 3 J to 3I in length ; pectoral about twice in head in male, shorter 



in female ; width of lower pharyngeals about 3 in the length, teeth 

 rounded, not entirely confluent. 



1. Dorsal and anal without blackish bars .... 2. glacialis. 



2. Dorsal and anal each with a row of blackish bars . . 3. pinnifasciata. 



B. Head 3J to 3J in length ; pectoral about i J in head in male, shorter in 



female ; width of lower pharyngeals 2 to 2J in length, the teeth more 



or less flattened and confluent ..... 4. putnami. 



These species form a natural group, which appears to connect Limanda and 

 Pseudopleuronecles on the one hand with Platichthys on the other. L. obscura is, 

 in many respects, very similar to Pseudopleuronectes, the lower pharyngeals being 

 narrower and less massive than in the other species of Liopsetta, and their teeth 

 conical and arranged in two rows. It agrees with the remaining species of Liopsetta, 

 however, in having the scales rougher in the male than in the female.^ 



Liopsetta glacialis, pinnifasciata and putnami are very closely related, and it 

 would perhaps be better to regard these as subspecies of a single variable species. 

 I have hesitated to adopt this course, however, as the material at my disposal is 

 far from adequate. 



1. LIOPSETTA OBSCURA (Herzenstein). 



Pleuronectes obscurus, Herzenstein, 1891, [Mel. Biol., xiii (l)] Bull. Ac. Imp. Sci. St. Petersbourg, 

 xxxiv (N.s. 11), p. 45. 



Liopsetta obscura, Jordan and Evermann, 1898, Bull. U.S. Nat. Mus., xlvii (3), p. 2651 ; Jordan and 

 Gilbert, 1899, Fur Seals and fur-seal Is. N. Pacif., (3), p. 492 ; Schmidt, 1904, Pise. Mar. 

 Orient., p. 244, tig. 20; Jordan and Starks, 1906, Proc. U.S. Nat. Mus., xxxi, p. 217; Pavlenko, 

 1 9 10, Trudui Obshch. Kazan, xlii. p. 59 ; Jordan, Tanaka and Snyder, 19 13, J. Coll. Sci. Tokyo, 

 xxxiii (i), p. 329 : Soldatov and Lindberg, 1930, Bull. Pac. Sci. Fish. Inst., v, p. 407. 



Liopsetta {Gareus) obscura, Hubbs, 1915, Proc. U.S. Nat. Mus., xlviii, p. 486. 



* Unfortunately, it has been impossible to ascertain the form of the pyloric caca in this species. 

 24 



