740 



DEPTHS OF THE OCEAN 



are very small (according to Gill and Ryder 0.7 mm. in 

 diameter). 



An important question is : Where does the spawning take 

 place .-* I do not believe in any general vertical spawning 

 migration among deep - sea pelagic animals, even if the 

 eggs develop in the upper strata of the ocean ; the eggs 

 themselves must rise to the surface. If this were not so, we 



Fig. 528. 

 Cydothonc viicrodon, Giinth. Nat. size, 6.3 cm. 



should undoubtedly have taken, in the upper layers, many 

 more of the pelagic fishes peculiar to deep water, whereas 

 we took them with ripe eggs in deep water. The eggs 

 captured and examined by us vary greatly in size and 

 Size of fish appearance; Fig. 530 shows the relative size of some of 



them. 



lall 



^^Z 



ittle 



than 



mm. m 



Fig. 529. 

 Gastrostomiis bairdii. Gill and Ryder. Nat. size, 76 cm. 



diameter, taken between the Canaries and the Azores ; B 

 and C are nearly ripe eggs from Cyclothone signata and 

 C. microdon (0.46 and 0.56 mm. in diameter) ; D is the ^^^ of 

 Gastrostomus bairdii. It is interesting to compare these with 

 the cod &^^ (E), especially when we consider the number of 

 eggs produced by this fish. Cyclothone signata, the eggs of 

 which are perhaps only one-tenth of the volume of the cod 

 eggs, has only 1000 eggs compared with the five million eggs 

 of the cod. 



