SEA-FISHERIES LABORATORY. 415 



A. E. Hefford, in his report on the teleostean ova and 

 larvae observed at Plymouth,* shows very clearly, from 

 comparisons of the egg' measurements of four species of 

 Gadoids, the uncertainty in correctly identifying some 

 of the pelagic fish eggs. The following table gives the 

 variation in size of the eggs of four common members of 

 the Gadoids and the size of the green cod egg, another 

 member of the same family, for comparison. 



Poor cod eggs ... ... 0"95 — 107mm. 



Bib eggs ... ... 1'05 — 1'15 mm. 



Pollack eggs ... ... 1'13 — 114 mm. 



Whiting eggs ... ... 1"069 — l"352mm. 



Green cod eggs ... 1'161 mm. 



The larval stages of the economic Gadoids found in 

 the Irish Sea occur in the area covered by the intensive 

 study investigations as early as the end of February. The 

 post-larval forms are found up to the end of May, after 

 which they probably sink below the surface and are not 

 captured by the surface nets. Preserved specimens of 

 the very young stages of Gadoids have a considerable 

 resemblance to each other. They are easily mutilated 

 in capture, and cannot often be identified with certainty. 



Molva vulgaris, Fleming. — Ling. 

 The characteristic pelagic egg of the ling, which 

 has a large smoky oil globule measuring 04 mm. 

 in diameter, was only found once in the plankton 

 collected at the south-west of the Isle of Man during the 

 six years' investigations. It occurred in a surface 

 collection taken on April 27th, 1908. The egg is 

 comparatively small, measuring about 1'08 mm. in 

 diameter, and the oil globule occupies fully one-third of 

 the interior. 



* Journal Marine Biological Association, N.S., Vol. IX, No. 1. 



