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Part III. — Seventh Annual Report 



tions of ova made with the surface-net at the beginning of the month 

 just outside the Bay (near the Bell Bock), the sizes and conditions of the 

 several ova are diagnostic. Thus the large ovum, with the wide perivi- 

 telline space, is characterised by t its translucency, and the isolated yolk 

 is readily seen in the early stage, just as the embryo with the diminished 

 yolk in the same large space is conspicuous in the later stages. The 

 embryo floats yolk uppermost at the high arch of the egg, leaving the 

 wide perivitelline chamber beneath it. Though the latter space is thus 

 peculiarly large, it is interesting that no real difference exists between this 

 egg and the others beside it. For instance, the young cod and its yolk 

 almost fill the egg-capsule, the yolk in the floating egg being uppermost, 

 while the body of the embryo stretches along each side of the lower pole, 

 its curvature being determined by the limited size of its envelope. On 

 the other hand, the embryo in the large egg is comparatively free, and 

 bends only a little over its own yolk, following, in short, the same relative 

 curvature that is seen in the more tightly enveloped cod. The yellow pig- 

 ment of the embryo, the minutely streaked capsule, and the comparatively 

 large size of the egg indicate that of the plaice. The size of the egg 

 of the haddock distinguishes it from that of the cod, and the characteristic 

 bands of pigment in the embryo of the latter (in the egg) render the dis- 

 tinction easy at that stage. The small size and bright yellow pigment in 

 the embryo differentiate the egg of the dab ; while the egg of the rockling 

 (probably 3-bearded) is still less, and has a single large clear oil globule at 

 its summit. The transparency of the egg of the sprat and the reticula- 

 tions of the yolk are also diagnostic. 



Post-larval gadoids from \ to J an inch, appeared at the end of the 

 month in the mid-water net, and some were procured during the month 

 south-east of the Isle of May. Larval sand-eels about f of an inch, and 

 various Clupeoids from \\ to 2 inches long, were likewise obtained. 



On the fine fishing grounds south-east of the Isle of May early post- 

 larval sand-eels were in great numbers near the surface, and were captured 

 in the tow-nets amongst the pelagic ova. The distribution of this form is 

 very wide, and though it is probable the ova are demersal, the pelagic 

 habits in the post-larval and young, and even of those of considerable size, 

 tend to spread the species throughout the neighbouring ocean. 



In stormy cold weather at the beginning of April, and with a high east 

 wind and rain, the bottom-net on one occasion was prolific in ova, such as 

 those of the dab, cod, haddock and rockling, whereas the surface-net gave 

 only one or two. Towards the end of the month the ova of the sprat 

 abounded in the bottom-net. 



Post-larval flounders, T 7 g to T %- inch long, were not uncommon ; while a 

 dab, I^q inch, gave a later stage in development, as also did a goby, If 

 inch long. 



In the same net (mid-water) larval sand-eels, Montagu's sucker, and 

 post-larval armed bull-heads (Agonus) occurred; young lump-suckers about 

 \ inch, and young Cotti inch long, also were captured. 



Though larval and post-larval armed bull-heads were not uncommon 

 in the nets, all the adults had not spawned, for in the beginning of the 

 month various females with nearly ripe eggs were found. Again, though 

 post-larval wolf-fishes (Anarrliichas lupus) must abound near the mouth of 

 the Bay, it is remarkable that none have ever occurred within it, more 

 especially as a mass of ova was found within the limits of the Bay in 

 January 1886. The post-larval wolf-fishes are active swimmers. 



In the trawl-like bottom-net young herrings were likewise procured in 

 great numbers at the beginning of the month, some of them having the 

 yolk-sac still present. The greater part of the Bay seemed to abound with 



