THE FLOUNDER FAMILY. 367 



Ireland. On the east coast of Scotland ripe forms are found 

 from April to August, but so far as known there is no migration 

 for the purpose of spawning. Ewart and Fulton conclude that 

 the chief spawning-period is in June, and the same period is 

 entered in the Scandinavian Fishes for Sweden, while Ehren- 

 baum for Heligoland gives the latter half of June and July. 

 The large adults frequent rough ground near the Bell Rock, 

 only the smaller forms occurring on the sandy ground in the 

 Bay. 



The eggs of the lemon-dab (Plate IV, fig. 15) are in 

 contrast with those of the plaice comparatively small, having 

 a diameter of '053 in. or about T35 mm. Besides the ordinary 

 pelagic characters they possess a slight sheen, a feature probably 

 due to the peculiar structure of the surface of the capsule, 

 which is minutely wrinkled, the ridges interdigitating with each 

 other in a complex manner somewhat like irregular basket- 

 work. A series of prominent interlacing ridges, generally 

 running obliquely into each other, covers the entire surface, 

 while the interspaces are filled with rather closely arranged 

 subordinate ridges (Plate IV, figs. 16 and 17). Under com- 

 pression the stratum shows a somewhat irregular reticula- 

 tion of pale streaks on the minutely punctured surface. 

 Cunningham describes the surface as showing a number of 

 fine raised ridges forming two systems of parallel lines which 

 cover one another diagonally. Holt, again, states that, seen 

 from above, the markings appear as a line to which the thickly- 

 set punctures of the rest of the capsule do not extend, and is of 

 opinion that the appearance is caused by sharp grooves indent- 

 ing the surface of the capsule from a quarter to half its 

 depth. The capsule in the lemon-dab is comparatively thick, 

 and the development of the embryo, though visible, is not seen 

 with that perfection of definition characteristic of more trans- 

 parent forms. During development the wrinkled surface some- 

 what resembles morocco leather. 



In the warmer months development is rapid. Thus in a 

 series fertilized on the 8th July at 8 p.m., no pigment occurred 

 till the fifth day (in Cunningham's it appeared on the fourth). 

 The pale processes found during the fourth day upon the head, 



