36 RBPHODUOTION AND DEVELOPMENT OF TELEOSTEAN EISHES 



drift-nets or seines to so great an extent. Its spawning and 

 development have been investigated by J. A. Ryder, a naturalist of 

 tlie United States Fish Commission, and an account of its fishery is 

 given by R. Edward Earll. Its ova are pelagic and closely similar 

 in all respects to those of Scomber scomber, but somewhat smaller. Oa 

 the coast of Virginia (Mob jack Bay, Chesapeake Bay) it spawns in 

 July, Ryder does not mention the mobility of the oil-globule ; he 

 states that it is fixed and to its position ascribes the buoyancy of 

 the egg, and the position of the egg when floating. Probably the 

 oil-globule is movable nevertheless, and there are several floating 

 eggs which have no oil-globule. Ryder describes the subsequent 

 formation of a mantle of cells, '' apparently of hypoblastic origin,'^ 

 round the oil-globule, and says that by the time the young fish is 

 ready to hatch, the covering of the oil-sphere is found to be more 

 or less covered with pigment which seems to have been developed 

 in the cellular mantle. This refers to the same processes in the 

 history of the oil-globule as I have described in the mackerel, but 

 the mantle round the globule is certainly not made of hypoblastic 

 cells, but of the periblastic syncytium, from which the pigment- 

 cells are developed. The development in Cybium is extremely 

 rapid, hatching taking place about twenty-four after fertilization ; 

 the temperature of the water in which the eggs were kept artificially, 

 or of the sea in which they ai-e shed naturally, is not stated by 

 Ryder. The mouth was formed about twenty-four hours after 

 hatching, by which time the yolk was almost entirely absorbed. 

 Some of the larvae were kept alive till the sixth day after hatching. 



Blennius ocellaeis. 



On July 10th I received at the Laboratory a large hollow bone, 

 probably the femur of an ox, affixed to the sides of the cavity of which 

 was a single layer of adhesive ova of an orange-red colour ; this 

 was forwarded by Mr. Dunn, of Mevagissey, who had obtained it 

 from some fishermen. It was brought up by a long line fifteen 

 miles south of Deadman Point, Cornwall, having been caught by one 

 of the hooks. In the letter sent at the time Mr. Dunn stated that 

 the fishermen said that when the bone was taken there was a fish in 

 the cavity of the bone, supposed to be guarding the eggs, but that 

 the fish had escaped and fallen overboard. The next day, however, 

 Mr. Dunn forwarded a fish which he said was the one that had been 

 seen in the cavity of the bone, the fishermen having found it at the 

 bottom of their boat and recognised it as the same. This fish was 

 a specimen of Blennius ocellaris, L,, and in all probability the ova 

 belonsred to it. 



