FISHES OF THE GULF OF MAINE 



453 



not sufficiently numerous nor is the identification of the eggs certain enough to 

 prove it. Neither can we establish the temperatures or salinities in which it spawns 

 most freely from the data yet gathered. 



The eggs are buoyant, spherical, transparent, and 0.72 to 0.76 mm. in diameter. 

 When first spawned there are variable numbers of small colorless oil globules 0.02 

 to 0.07 mm. in diameter scattered over the yolk, but shortly after fertilization has 

 taken place most of these globules unite into one large one of 0.15 to 0.17 mm., which 

 is sometimes alone but usually has two or three tiny ones close beside it. Within two 



Fig. 223.— Locality records for squirrel hake eggs • and for larva of rockling (A) in the Gulf of Maine 



days after fertilization (at a temperature of 60°) the embryo extends half way around 

 the yolk sphere and pigment has appeared, one of the most characteristic features of 

 this species being the development of black chromatophores not only on the embryo 

 but over the yolk and finally on the oil globule as well. In late stages of incubation 

 this feature, combined with the small size of the egg and (usually) with a multiple oil 

 globule, distinguishes the egg of the squirrel hake from all other buoyant fish eggs of 

 known parentage yet found in the Gulf, except that of the rockling (p. 461), which is of 



