FLOUNDERS OF GENUS PARALICHTHYS AND KKLATED GENERA 



299 



within the ^nus. Two dissected specimens of 

 Icthostigma examined by me give counts of 1 1 +:^7 

 and 10 + 27; of three specimens of denfaf >/.-:, two 

 liave 11+30 and one has 11 +31 ; one .iq-iMmilejitus 

 lias 10 + 28 and one trojneus has 10 + 26. Jordan 

 and (loss (Kept. U. S. Comm. Fish. 1886, ])]). 243- 

 2-15, 188D) report the ntiiuber of A'ertehrae as: 

 rnlifo7mi(yus 10 + 25, dentatus 11 + 30, alhiguttn and 

 lethostigmu 10 + 27. 77. uhlonga 11 + 30. Tliomp- 

 son (Proc. U. S. Nat. Mus.. vol. .50, p. 411, l'.)l()) 

 records the vertebrae of hrasHieims as 11 + 23. 

 Tlie number of vertebrae is. tlierefore, subject 

 both to individual variation and to specific ditier- 

 ences, and the numbers found in the American 

 species which are universally accejited as boinii 

 congeneric, cover the range of both Psendo/hom- 

 hxhs and Paralichthyfi as given by Regan. Conse- 

 quently, no two genera can be distinguished on 

 that basis. 



This leaves the absence of accessory scales as 

 the best character by which P.sf'U(IarJiomhii^'< may 

 be distinguished from Paralichthijs. This char- 

 acter is discussed on page 284. 



PSEUDORHOMBUS ISOSCELES 



(PLATE 5) 



DiagTioKls. — Scales ctenoid on both sides, except 

 those on cheek and opercle of blind side; 4(1 to .">() 

 (counted on blind side in the three specimens ex- 

 amined, scales (m eyed side largely fallen off); 

 perforate scales 24 to 28 in arch and 50 to .M in 

 straight part to end of hypural. Accessory scales 

 absent. Gill rakers on lower limb 8 or 9, com- 

 paratively short; upper limb with one gill raker at 

 angle and 3 to 5 tul^rosities above but slightly 

 raised. Anal rays 66 to (58; dorsal rays 82 to 84. 

 Pectoral 11, sometimes 10 (11 on both sides in two 

 specimens, 10 on blind side, and 11 on the other 

 in one specimen). Origin of dorsal in front of 

 anterior margin of eye. Interorbital narrow, but 

 wider than a mere ridge. Eyes rather large. 

 Anterior teeth vei-y moderately enlarged. Maxil- 

 lary reaching posteriorly to a vertical through 

 hind margin of eye or not quite that far. Depth 

 47 to 49.8, maxillary 13.9 to 14.:i. head 26.9 to 29.3, 

 u])per eyeball (i to 6.4, up])er orbit 7.5 to 7.9, inter- 

 orbital 1.3 to 1.6 (range of 3 specimens 243 to 260 

 nun.). Sinistral. 



Color. — The color is nearly faded. Two large 

 ocellated spots distinct, situated on a vertical al- 



most midway between shoulder girdle and base of 

 caudal, one at a short distance below the dorsal 

 profile, and one at an equal distance from the 

 ventral profile. A definite prepeduucular spot is 

 not now present; but Jordan describes it in his 

 original account, and a trace of such a spot is 

 faintly perceptible. Ventral of eyed side with a 

 small, oblong, roiuided black spot at its distal 

 margin. 



tS/tecinien,s examined and geographic dififrihy- 

 fioii. — ^This account is based on three of Jordan's 

 original specimens from Bahia. Brazil, 243-260 

 nun. (43335; 43.")68; 43371, herewith designated as 

 the lectotyi^e. 247 mm.). Norman's record (1937) 

 extends the range of the species southward to lati- 

 tude 45°05'. 



Distinctive characters and relationship. — This 

 si^ecies has ctenoid scales on the blind side, unlike 

 any species of Paralichtkys. It also lacks acces- 

 sory scales. In these two charactei's it agrees with 

 the species of Pseudorkomhus. No other, more 

 substantial characters, are now known by which 

 the two genera may be delimited, and if they are 

 recognized as distinct at all, isosceles should be 

 placed in Pseudorhomhits. In their general ap- 

 pearance, i-egularity of arrangement and sharply 

 defined edges, the scales of isosceles resemble those 

 of Pseudorhombus oligolepis (Bleeker) with 

 which it was compared. This sjiecies is readily 

 distinguished from all closely related species of 

 the M'estern Atlantic, except Hippoglossina ol)- 

 lohgn^ by the piesence of ctenoid scales on both 

 sides. It diffei's from H. oilonga in having fewer 

 scales, in having nearly all scales ctenoid and more 

 strongly so, in the color i)attern and in other char- 

 acters given in the key. 



This species. H. ohlonga and //. fetrophthahmts 

 have a black spot on the ventral of the eyed side. 

 Attention is here called to this fact; because the 

 ])ossessiou of certain color nnirks in common, is 

 often a good indicator of close relationship in 

 fishes. 



I'lirnJirhtlnix ixoscrh'x .torilan, Proc. T^. S. Nat. Mus. 13: 

 .S:{0. l.S!)(> (I!:ihia, Brazil ).—Ni)i-niaii. Mmnpsir. Flallishes, 

 p. SO, V-VM (liiised on original accdunt). 



PuiiidorhoDibiis isnitcelcs Uinsl)urf;, Jour. Washington 

 Acad. Sci. 26: 131. 1036 (systematic position iliscusscd l. 



PdinliihtltjiH iiiasci ics Norman, Di-scovery Rept. 16: 134, 

 1937 (from four stations off the coast of Argentina be- 

 tWiH'U lulimdcs 43°o0' and 4r)°05'). 



