THE FLOUNDER FAMILY. 397 



oil-globules, the whole surface of the yolk is dotted with minute 

 granules of oil, as indicated in the figure. Holt mentions that 

 in his examples the oil-globules were restricted to the vegetative 

 hemisphere, both in the early and advanced stages of the egg — 

 a condition which differed from that in either of the eggs 

 figured, so that probably a change subsequently occurs. In the 

 egg of April, the yolk was invested by a conspicuous layer of 

 protoplasm, which fixed the majority, if not the whole of the 

 globules, and in a ruptured egg it could be observed to peel 

 from the yolk, carrying the oil-globules in its folds. A similar 

 belt of protoplasm is seen in the ordinary egg of the solenette 

 in Plate IV, fig. 11 ; and as no trace of yolk-spheres occurred 

 in the eggs of April and May, and only a few small ones in the 

 last-mentioned figure, it may be that both are early stages, and 

 perhaps those of April and May unfertilised. The rarity of the 

 latter condition, however, in pelagic eggs is well known. It is 

 also noteworthy that an egg resembling the ordinary egg of the 

 solenette occurred at the surface, whereas the form alluded to 

 here came from the bottom. Considerable latitude, however, 

 must be given both in regard to distribution and to the size of 

 the oil-globules. 



Specimens of the 23rd June (captured in St Andrews Bay), 

 in which the disc was beginning to spread out, had the main 

 oil-globules at the vegetal pole, and only a few smaller at a 

 lower level — one or two approaching the centre. On the 25th, 

 the tail of the embryo was free from the yolk, which was marked 

 by delicate reticulations, while pigment of a pale or dull whitish 

 colour was developed over the head, body and yolk-sac. They 

 were hatched about the 4th day afterwards, this period agreeing 

 with what Holt found on the west coast of Ireland, or about 

 5 days in all. In the larval fish (Plate XVIII, fig. 1), which 

 measures about 2'02 mm., the elongated form of the otocysts, 

 the large oil-globules, which, with one or two smaller, form a 

 row along the posterior curve of the globular yolk-sac, and the 

 whitish-yellow pigment (somewhat like that of the common 

 sole) are diagnostic. The breast-fins have a bar of the same 

 pigment. The bend of the gut to the left (when viewed from 

 the dorsum) is marked, and the reticulated condition of the 



