FLOUNDER-FISHES. 
421 
THE ROUGH DAB (sw. lekflundkan). 
DREPA N 0 PSETTA PLATESSOl 1 )ES. 
Plate XVII, fig. 3. 
Jaw-teeth set in a single row both in the upper and the lower jaw. Brancliiostegal rags -s’. (rill-rakers on the 
first branchial arch at most 15. Length of the branch of the lower jaw on the blind side more , on the, ege side 
usuallg less , than half the length , of the head. Scales of the bodg firmlg attached,, on the ege side extending over 
all the fin-rags and, in front , at least par tig, over the jaw-bones. Lateral line without dorsal branch in a back- 
ward direction. Total length of the head purging between 20 and, 23 % a of the length of the bodg, its postorbital 
length between about 12 and 14 % h thereof. Coloration of the ege side grayish brown with a dash of red, spotted 
with dark brown; blind, side bluish white. 
R. br. 8; D. 76— 93 e ; A. 64— 73 d ; P. 10 — 13 e ; V. 6; 
C. .*+12 1. 14+.*.; Lin. lat. 85 — 102 ( + 20 — 25 in pinn. caudali); 
Vert. 45 1. 46. 
a: Forma platessoides, americana: altitud. max. corporis )> ,{, V 100 
longit. ejusdem; altitud. minim, corporis > ! 4 longit. mandib. 
in latere oculari. Num. rad. pinn. pector. 12 1. 13. 
Syn. Pleuronectes platessoides, Fabr., Fn. Groenl., p. 164; D. Vid. 
Selsk. Naturv., Math. Afh., vol. I, p. 50; Reinh. (Citharus ; 
nom. gen. antea usurp.), ibid., vol. VII, p. 130; Ke.. Voy. 
Scand., cett. (Gaim.), tab. 21; Gill ( Drepanopsetta ), Proc. 
Acad. Nat. Sc. Philad. 1861, App., p. 50; ( Hippoglossoides ), 
ibid. 1864, p. 217; Br. Goode, Proc. U. S. Nat. Mus., vol. 
3 (1880), p. 471 ; Jord., Gilb., Bull. U. S. Nat. Mus., No. 
16 , p. 826 . 
Hippoglossoides limandoides , Goode et Bean, Amer. Journ. Sc., 
Arts., vol. XVII (1879), p. 39. 
b: Forma limandoides, palmarctica; altitud. max. corporis <C ' !o / ln0 
longit. ejusdem; altitud. minim, corporis <C 72 / ]00 longit. 
mandib. in latere oculari. Num. rad. pinn. pector. <C 12. 
Syn. Pleuronectes linguatula, Pontopp., Dansk Atl. I, p. 649, tab. 
27; Mull., Zool. Dan. Prodr., p. 45, No. 377; Retz., Fn. 
' Sue c. , Lin., p. 332; — nee PL linguatula Linn.®i, quae spe- 
cies ex Art. et Willugiib. = Citharus linguatula auctt., in 
mari Mediterraneo; vide Fries, Vet.-Akad. Handl. 1838, 
p. 179. 
Pleuronectes limandoides, Bl., Ausl. Fisch., part. Ill, p. 24, 
tab. CLXXXVI: Qvens., Vet.-Akad. Handl. 1806, pp. 54 et 
222; Fab., Tidskr. Naturv., V (1828), p. 244 et Isis, 1828, 
p. 878; Nilss., Prodr. Ichtli. Scand., p. 57; Schagerstr., 
Physiogr. Sallsk. Tidskr., p. 312; Parn. ( Platessa ), Wern. 
Mem., vol. VII, p. 368, tab. XXXVIII; Sund. et v. Wright 
( Pleuronectes ), Skand. Fisk., ed. I, p, 117, tab. 27; Kr. 
(Platessa), Damn. Fislce, vol. II, p. 358 et vol. I, p. 611; 
Nilss. ( Pleuronectes ), Skand. Fn., Fisk., p. 629; Gtiir 
( Hippoglossoides ), Cat. Brit. Mus., Fish., vol. IV, p. 405; 
Coll., Forh. Vid. Selsk. Christ. 1874, Tillaegsh., p. 136; 
Malm, Gbgs , Boh. Fn., p. 509; Winth., Naturh. Tidskr. 
Kblivn, ser. 3, vol. XII, p. 37 ; Day, Fish. Gt. Brit., Irel ., 
vol. II, p. 9, tab. XCV ; Mob., Hoke, Fisch. Osts., p. 88. 
Ilippoglossus ( Hippoglossoides ) Limanda, Gottsche, Arch. 
Naturg., Jahrg. I, Bd. 2 (1835), p. 168. 
Drepanopsetta platessoides, Malmgr., Ofvers. Vet.-Akad. Forh. 
1864, p. 525; Coll. (Hippoglossoides), Forh. Vid. Selsk. 
Christ. 1878, No. 14, p. 92; ibid. 1879, No. 1, p. 74; 
Norsk. Nordh. Exped., Zool., Fiske, p. 114; Lillj., Sv., 
Norg. Fn., Fisk., vol. II, p. 299. 
Obs. In recent times it has been the general practice to follow 
Collett’s example and identify the Greenland and North American Dre- 
panopsetta platessoides with the European Drep. limandoides; and it 
cannot be disputed that the difference between them is only slight. Even 
in his Catalogue (1. c.) Gunther suspected that these two species 
were identical. However, he could not defend his opinion by person- 
ally comparing American and European specimens. Now, on making 
such a comparison — though we have had only three American speci- 
mens, one male and two females — we find the differences between 
them far too important to admit of our unhesitating assent to the 
identification of the two species. It is true, as Collett has pointed 
out, that in the European form the number of rays in the dorsal and 
anal fins is so inconstant that, as a rule, the specimens that live in 
the far north have more rays in these fins than the inhabitants of 
more southern regions. Whether this rule also applies to the Ameri- 
can form, is as yet unknown; but in the specimens of the Royal 
Museum we find at least one exception. In a specimen (9) taken at 
Ivigtut by the Sofia Expedition in 1883 the formula is D. 93, A. 73, 
while in a specimen (9) taken off Holsteinborg by Dr. 6berg it is 
D. 80, A. 67. Hence we see that, even within the limits of the 
Arctic fauna, the variation may be considerable. Collett has also 
given sufficient evidence to show that the. number of these rays is 
untenable as a specific character. On the other hand, to judge by 
many other species, it seems probable that the difference shown by 
the specimens of the Royal Museum in the number of rays in the 
pectoral fins, is more constant. To this we may add the deeper form 
" Between 20'3 and 23'0 % in the specimens which we have examined, and which were between 228 and 396 mm. in length. Ac- 
cording to Collett this proportion sometimes exceeds 24 or even 25 %, a character which otherwise belongs to the fry. 
b Between 11*9 and 14'1 in the specimens which we have examined. 
c Sometimes as many as 101, according to Collett. 
d Sometimes as many as 79, according to Collett. 
c On the blind side somelimes 9. 
