198 NORTH SEA INVESTIGATIONS. 
ray formula was D, 63—74, A. 47—55. The formula of all which 
I have examined is therefore D. 63—75, A. 47—55, and it is evident 
from the condition in those separately enumerated that the formula 
shows no grounds for suggesting a distinction, other than sexual, 
between the ciliate and smooth examples. I have omitted to tran- 
scribe the proportions, as they differ in no degree inexplicable as 
individual variation. 
The inferences which appear to be permissible from the details 
enumerated above are as follows :—(1) The female, in these dwarf 
Baltic plaice, is either smooth, or ciliated only on the head. (2) 
The male is almost always more or less ciliate ; perhaps always ciliate 
when mature, the ciliation increasing with the growth of the fish. 
I may add that none of my examples show the ciliation especially 
conspicuous along the lateral line, though this has been given as a 
character of Pl. pseudoflesus. 
It would appear, then, that the variety last named is merely the 
male of what Gottsche considered to be the typical form of Pl. 
platessa, t.e. the “gold butt.” The “‘scholle,” the variety Pl. borealis 
of the same author, appears to be the ordinary North Sea plaice. 
Apart from these Baltic fish, | have met with instances of ciliation 
in two other examples of the plaice. The first was a mature male, 
19% inches in length, taken in April of the present year on the Great 
Fisher Bank. In colour and general appearance it resembles a 
number of normal examples taken at the same time, but the scales 
on the ocular side have about 8 to 10 very short pectinations in the 
central region of the posterior edge. On the blind side the scales 
are either smooth or only very feebly ciliate. 
The other example is a male from Iceland, 244 inches long. The 
cilation of the ocular side is much the same as in the Fisher Bank 
specimen, but the scales of the blind side are smooth. In both ex- 
amples the scales of the caudal region imbricate to some extent, but 
not more than in smooth fish from the same locality, and the ciliation 
is by no means confined to this region of the body. 
There is good reason to believe that there is a regular migration 
of plaice between the Fisher Bank and the north-west coast of 
Denmark (and probably also the Sound), and that, in fact, the Fisher 
Bank plaice are reared on the Danish coast. It is not, therefore, 
surprising that ciliate examples should be met with both on the 
Fisher Bank and at Histholm. 
It seems probable enough that the characters of ciliation and size 
would be found to vary in a degree corresponding to the locality if 
a series could be obtained from the different parts of Denmark, from 
the Baltic to the southern region of the North Sea coast. No such 
material, however, is available, and all that can be said, in view of 
