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Part III. — Seventh Annual Report 



In the surface-net the pelagic bivalves, chiefly mussels, were compara- 

 tively few at the commencement of the month, but towards the end 

 they were more abundant. The measurements of the young mussels 

 ranged from '0125 to *015 of an inch. A few specimens of the larval 

 stages of Spinalis also occurred as a rule, and larval univalves, probably 

 including Natica. During this month also the pelagic mussels are met 

 with far out at sea. 



The mid- water net captured very few mollusks this month ; the 

 specimens, apparently young mussels, which were procured on the 20th 

 and 23rd, ranging from -009 to *0155 inch. As none were observed last 

 month in this net, they must either have passed through the meshes or 

 were now only risiug from the bottom. 



The bottom-nets, on the other hand, in almost every instance showed the 

 young mussels in multitudes ; indeed, this could hardly have been other- 

 wise in view of the wonderful profusion of animal life they brought to the 

 surface. During the latter half of the month they occurred in myriads. 

 In size they varied from 'Oil to "023, and on the 31st some appeared to 

 be elongating a little. In company with these w T ere young examples of 

 Sjririalis, which — somewhat few in number in each net in the earlier 

 part of July — became much more abundant towards the end of the 

 month. Some of these were in the earlier stage, others more advanced, 

 but most were young examples. Other larval bivalves of unknown 

 relationships (but probably of well-known forms) were also present, and 

 several univalves, some of which most resembled the young of Natica. 



In July the ova of Modiolaria marmorata and Astarte sulcata are 

 fairly developed, and some probably spawn at this period. 



The pelagic ova of July were comparatively few in species, consisting 

 towards the beginning of the month of a few eggs of the gurnard. One 

 of the most interesting ova of the whole series, however, also occurred 

 at this time, viz., that of the sole, a few of which were captured 

 about the same period in the mid-water net. They measured *045 of an 

 inch. The capsule is thick and tough, as well as minutely punctured. 

 The oil-globules are of a yellowish white appearance by reflected light, and 

 form a more or less complete ring of groups of minute globules. More- 

 over, the border of the yolk is vesicular. During development the groups 

 of oil-globules change their position, and lie along the ventral surface of 

 the embryo. The observations of Raffaele on the Neapolitan pelagic 

 eggs demonstrate the connection of this ovum with the sole. During 

 the Trawling Expeditions in 1884, the ripe eggs of the sole had been 

 removed from the female fish on the 1st August, but no note was 

 made of their difference from the ova of the other Pleuronectids. Mr 

 Cunningham observes that the sole spawns in winter and spring, and 

 from the appearance of the ovaries of specimens examined in November 

 he considers this correct for the southern waters (Plymouth). It would 

 appear to be different in our neighbourhood. 



In the open sea pelagic ova measuring *034 were procured off the 

 Firth of Forth, which probably belonged to Motella ; while smaller forms 

 (•022 inch), off St Abbs, are still undetermined. Both of these were 

 captured near the surface. 



In the beginning of the month various small flounders, ranging from 

 6 '5 mm. to 12*5 and 18 mm., were procured in the trawl, showing that 

 they were even then seeking downwards. The smallest had the eyes 

 lateral, though the left was slightly advanced, and pigment on both 

 sides of the body, but the fin-rays were well developed for its size. 

 The others had pigment on the right side, and the left (or under surface) 

 white. 



