NORTH SEA INVESTIGATIONS. 197 
caudal fin. The blind side has the semi-translucent whiteness 
characteristic of normally coloured plaice. 
Most of the smooth examples which I examined had only small 
pale orange spots, rather few in number and remote from each other, 
Such was also the case in only slightly ciliate examples, but both 
series showed intermediate degrees of coloration, rendering it 
impossible to draw any absolute distinction based on colour alone, 
While dealing with the coloration it is worthy of remark that 
amongst a number of flounders (Pl. jflesus) present in the consign- 
ments of small plaice, some were pigmented in very much the same way 
as the most ciliate of the plaice, but had no dark pigment, while the 
blind side was dead white. Other flounders in the same consignment 
were uniform brown or blackish brown (on the ocular side). 
The flounders were very much more spinous than any which I 
have seen from our own coasts, practically the whole of the ocular 
surface being in some cases covered with rough tubercles, which 
were also present to a considerable degree on the blind side, 
According to Smitt (op. cit., p. 397) Scandinavian flounders appear 
to be also more spinous than our own, in which the tubercles, accord- 
ing to my experience, are confined to the lateral line and the bases 
of the dorsal and anal fins. On examining examples from the Atlantic 
coast of Denmark I find some in which the spinulation is rather in 
excess of that exhibited by British specimens, a condition which 
might be expected from the intermediate position of the locality. 
To return to the Baltic plaice, I handed over a series of ciliate 
and non-ciliate examples to Dr. Giinther, who suggested that the 
ciliate ones were the males. I know of no observations which 
support such an opinion, but, on examining those which I had 
reserved for my own use, I find that it appears to be correct. 
I append a list of the fish examined for this purpose. 
Tuches long. 
A. 121... Smooth; female; mature oh ss aa spo UE Ys A. 55 
15), US oe 3 3 3 ae bie one PNR Ce ap Bl 
Ce s1O® os 55 si $s Ks ae oe be Sees Od sy» D4 
DEON os. % male; immature See eee aes ek Gee LOL woos RDO 
E. 12 ... Head feebly ciliate; female; mature ... ae So iGOl eee | too 
F. 9... Head and interspinous regions ciliate; male; mature _,, 67 AeA SIL 
(Cia Eases 3 x 5 5 3 OU baLe. 651 2 
H. 83 ... Ciliation extending a little on to trunk __,, a Ae refer RRA P- 
J. 93 ... Intermediate between H and L 53 * RON aie P55 p4S 
Ke92 os. » ” 99 H SLO sncca e s5, OA 
L. 111... Everywhere ciliate except in immediate neighbourhood 
of pectoral; male; mature ... oa S00 ioc tune Cote poco Bernas: 
The details of ciliation given above refer to the ocular side. 
In ten other non-ciliate examples, all or nearly all females, the fin- 
