ARCTIC CODS. 
481 
As we are still ignorant of the changes of deve- 
lopment of Gadus ogac in its younger stages, we must 
indeed confess the possibility that the limits of the va- 
riations may cross even in the character derived from 
the breadth of the interorbital space; and in this case 
Gad us ogac must be regarded simply as a form-variety 
of the same species as the Common Cod. In whatever 
way this point may be decided by a more complete in- 
vestigation of G. ogac , it is quite certain that this form 
comes so near the Common Cod in its entire structure 
that these two forms must have had a common origin 
at no distant period. To judge by the tendency of the ; 
changes of growth, Gadus call arias is less removed from 
this origin, and G. ogac seems to be a more purely 
Arctic branch of this stock. The theory propounded 
by S. Loven to explain the peculiarities of the Baltic 
fauna, with its numerous connexions with Arctic forms, 
on the hypothesis that there anciently existed an imme- 
diate communication between the waters where these two 
faunae now live apart, finds another support here: a form 
of G. ogac may once have inhabited the Baltic, though 
its characters, if this be true, have grown more in- 
distinct, while they have been persistent in the Arctic 
Ocean itself, on the coast of Greenland". 
Fig. 119. (Jaclas navaga , cA 2 3 of the natural size. Archangel, 1878; Lieut. H. Sandeberg. 
The other two Arctic species — or probably varie- 
ties of the same species — which come remarkably near 
the Cod, are the Russian navaga or novaga , as it has 
sometimes been called, (tig. 119) and wachnja 1 ' (Plate 
XXII, A, fig. 3: Gadus gracilis, by the natural size. 
Pitlekaj, 21st Oct. , 1878; Vega Expedition). The for- 
mer'' has long been known in Russia, where it is caught 
in large quantities in the White Sea, and conveyed in 
winter, in a frozen condition, to St. Petersburg and 
Moscow, where it ranks as a delicacy. The latter on 
the other hand, was stigmatized by Steller as neither 
of good flavour nor nourishing, being therefore thrown 
to the dogs. Turner gives wachnja the same character; 
and it was long rejected by the crew of the Vega , ac- 
cording to Nordenskioed, on account of the grayish 
green colour of the bones. Both are distinguished from 
the Cod by the comparatively smaller size of the head 
and more elongated form of the body; and both are 
remarkable for the singular lateral processes from the 
air-bladder, which tit into the above-mentioned cavities 
in the transverse processes of most of the posterior ab- 
dominal vertebra? b On this ground Fischer proposed 
a The fin-formula in Gadus ogac according to our investigations is: D. 14 — 1519 — 20[l8 — 20; A. 20 — 23 18 — 19; P. 18 — 19; 
V. 6; C. ,v + 20—25 +cc. 
b The name of wachnja , according to Steller, is a Russian corruption of the Kamchatkan aakal. According to Nordqvist (Vega-exp. 
Vet. Iaktt., l:sta Bd. p. 396) the Chukc-hees call the Cod urokadlin and the Polar Cod ( saida ) nalccin. The Esquimaux, according to Captain 
Jakobsen, pronounce ogak almost as oouk. The root of all these words seems to be the same. 
c Kolkeutek (Nov. Comment. Acad. Sc. Petrop., vol. XIV, tom. I (1770), p. 484, tab. XII) is generally quoted as the inventor of 
the specific name of Gadus navaga, though, like Tilesius (Mem. Acad. Petersb. tom. II (1810), p. 352), he expressly identifies navaga with 
Linnaeus’s G. callarias. Lepechin declared the form to be a distinct species (Nov. Comm. Petrop., tom. XVIII (1773), p. 512, not.), but gave 
it no systematic name. Pallas ( Zool . Rosso-Asiat,., Ill, p. 196) was the first to give it a full binomial designation. 
d Gadus gracilis, Til., 1. c., p. 354, tab. XVIII, XIX, XX; Jord., Gilb., Bull. U. S. Nat. Mus., No. 16, p. 804. Gadus wachna, 
Pall., 1. c., p. 182. Gadus navaga, Nordenski., Vegas fcird bring Asien och Europa, l:sta delen, p. 465; Smitt, Gt. Intern. Fish. Exh. 
London 1883, Swed. Cat., p. 176. Tilesia gracilis, Turner, Nat. IPist. Alaska, p. 90, pi. 3. 
e Cf. Fischer, Mem. Soc. Natural. Moscou, tom. IV (1812 — 13, reimprimes en 1830) pp. 257 et 259, tab. I'll, figg. 2 — 4; Baer, 
Bull. Scient. Acad. Sc. Petersb., tom. Ill, p. 359. 
Scandinavian Fishes. 
61 
