POOR COD. 
499 
Throughout this table, where the averages in Ga- 
< lus minutus increase with age, the averages are greater 
in Gadus luscus than in the former species; and where 
the averages decrease with age in Gadus minutus , they 
are also less in Gadus luscus. Thus the two species, 
if one chooses to call them so, stand in a very intimate 
developmental relation to each other; and the gaps be- 
tween the maximum and minimum proportions given 
above would no doubt have been tilled in most cases, 
if not in all, if Ave had been enabled to examine 
younger specimens of Gadus luscus. Between the largest 
specimen of Gadus minutus (210 mm. long) in the 
possession of the Royal Museum and the smallest 
specimen of Gadus luscus (297 mm. long) the gap 
is sufficiently Avide to admit of considerable changes 
of groAvth. 
We have just seen Iioav Gadus navaga and G. gra- 
cilis afford the same example of almost identical forms 
whose right to the position of independent species may 
Avell be questioned, the resemblance between them being 
so close that the existing differences may Avell lie re- 
garded as the expression of local variations. The case 
is the same here. The true home of the Bib evidently 
lies round the British coasts, for to the north and south 
it becomes rarer and rarer, the further Ave go from this 
centre; but in Scandinavian Avaters and, still more fre- 
quently, in the Mediterranean its juvenile stages occur 
with a certain degree of independence in form and 
colour. That these younger forms, even in English 
Avaters, should keep apart from the older ones, at dif- 
ferent depths and, in most cases, on different bottoms, 
coincides Avith our knoAvledge of the other Codfishes 
at different ages. Finally, to judge by the observations 
made up to the present, the Mediterranean capelan is 
distinguished from the Scandinavian Poor Cod only by 
its still closer affinity to the Bib. 
The folloAving group in the Scandinavian fauna 
contains three species, one of Avhich, Gadus Esmarkii , 
never attains the same size as the others, and retains 
several characteristics in common with their juvenile 
stages. Still, it is distinguished from them in several 
respects by the distinct direction of its development, 
and also, by the persistency of the barbel under the chin 
even in its adult state. Gadus Esmarkii thus ranges 
itself nearer the common origin of all the Cods; and 
of the true Coalfishes, the Pollack and the Coaltish, the 
latter is the further advanced in those respects in Avhich 
all three species sIioav a common direction of development. 
This appears most distinctly, according to our investi- 
gations, in the folloAving respects: 
Average in 
Gadus Esmarkii. 
Gadus pollachius. 
Gadus 
virens 
2 
specimens. 
3 
specimens. 
3 
specimens. 
3 
specimens. 
3 
specimens. 
2 
specimens. 
Length of the body expressed in millimetres 
in 
173 
33.2 
204 
362 
105 
300 
Least depth of the tail in % of the length of the lower jaw _ 
30.i 
40.8 
41.i 
43.7 
44.9 
Length of the snout „ ,, ,, ,, ,, ,, „ „ „ 
50.3 
53.3 
56.o 
58.9 
65. i 
69.3 
