of the Fishery Board for Scotland. 



213 



of fishes frequenting the bottom ; yet the three former have ova with a 

 somewhat thick investment, while the latter has pelagic eggs. In the 

 same way the pelagic herring has ova which are fixed to the bottom, 

 while the equally pelagic coal-fish has ova which float. Again, the rock- 

 ling, which frequently occurs between tidemarks, has pelagic eggs, while 

 the father-lasher (Cottics) has thick-shelled eggs deposited on the bottom. 

 Habit, therefore, has little relationship with the differences in this respect, 

 which seem rather to depend on phylogenetic causes. 



YarrelVs Blenny. — Nothing is said about the breeding of this fish in 

 recent works. A female in August (18th) presented small ovaries with 

 only traces of ova; while in another, on 29th November, the ovaries were 

 considerably enlarged, so that the ova were readily distinguished by the 

 naked eye. In all probability, therefore, this species spawns early in the 

 year. 



Gunnel. — Day (' British Fishes ') observes, ' Nilsson states its spawn 



* to be deposited in November. Mr Peach, however, in June believed he 



* discovered the spawn of this fish at Fowey, in Cornwall.* From the 

 state of the reproductive organs in August the spawning period would 

 seem to be distant, yet no signs of maturation had been observed in 

 those examined earlier in the year. 



Cat-fish. — Some rather small examples of this species have been pro- 

 cured. Thus, on 11th July a specimen, 6| in., 5th August another, 7f, 

 and on the 27th of the same month, a third, 8 J in., were obtained. A 

 fourth (18 inches in length), now living in the tanks, was procured by 

 the liners. All were captured by the latter on hard ground between the 

 Island of May and the Fife shore. 



Viviparous Blenny. — In July the ovary of this fish presents a somewhat 

 spindle-shaped aspect, the greatest diameter in a specimen about 10 inches in 

 length being one-third of an inch. The ova are of a straw-yellow colour, 

 and are attached to the wall by a pedicle. They show a coarsely globular 

 yolk with germinal area and spot, so that they do not appear to be impreg- 

 nated. Many of these ova are nearly equal in size, and they are sur- 

 rounded by a vascular investment presenting beautifully reticulated vessels. 

 Until the ovum, therefore, reaches a certain stage of development the access 

 of the spermatozoa cannot take place. 



At this season the males have the testes much enlarged, and the sperm- 

 cells contain numerous sperms, and some of the latter even occur around the 

 external aperture. In November, on the other hand, these testes diminish 

 greatly, while the ovary of the female is filled with young progeny. The 

 fluid in the ovary containing advanced young is nearly translucent in the 

 uninjured fish ; but shows under the microscope various blood-corpuscles 

 in a degenerating condition, the ovoid form being altered, and their bulk 

 considerably diminished, besides many granules. 



Tope. — A fine female example (4 ft, 8 in. long, with a girth of 21 in., 

 and expanse of tail 11 J in.) was captured in the salmon-nets on the 22nd of 

 August, but unfortunately the viscera had been so crushed that they were 

 almost useless anatomically. The ovaries presented many small ova, some 

 reaching ^th of an inch in diameter. The stomach of the specimen con- 

 tained a considerable number of herrings. 



Thornback. — Our present knowledge of the breeding of this species is 

 comprised in the following remarks * : — ' Begins to germinate in June, and 



* brings forth its young in July and August (Pennant). Egg deposited in 



* May and June (Couch).' Mr Day also quotes Couch's opinion that one of 

 the causes of the diminution of the species is tearing up of the ground by 

 the beam-trawl, so as to destroy the shelter necessary for the perfection of 



* Day, British Fishes^ ii. p. 345. 



