THE MARINE FAUNA AND THE OVA OF FISHES. 201 



They can be obtained and fertilized witli the greatest ease, 

 as in June and July a large proportion of every catch are 

 ripe fish of both sexes. After explaining to Mr. F. Johns, 

 the skipper of a mackerel boat, the necessary operations, 

 and promising him payment for his trouble, I found he could 

 bring me mackerel ova properly fertilized and in good con- 

 dition whenever he shot his nets. The mackerel is another 

 species which could be artificially propagated to any desired 

 extent. The eggs of the mackerel are closely similar to 

 those of the cuckoo-fish ; they have a single oil globule and 

 an otherwise homogeneous yolk ; they are buoyant and 

 transparent. 



Pilchard ova have not yet been obtained. In the case of 

 mackerel and herring the fishing- season and the spawning 

 season coincide ; in the case of the pilchard there is no fishery 

 in the spawning season. The pilchard leaves the shore when 

 spawning, and at that time, June and July, no shoals are met 

 with. But spawning specimens are caught occasionally in 

 small numbers in the mackerel nets, and it is from some so 

 taken that I expect before long to get some fertilized ova. 

 Now that the supply of salt water in the Laboratory is at 

 last available, the examination and the hatching of the eggs 

 of fish becomes comparatively easy, and it may reasonably 

 be hoped that these preliminary results will be rapidly 

 extended. 



VOL. r, NO. II. 14 



