30 DEEP-SEA FISHING. 



were still so imperfectly developed that it was hardly 

 possible to determine the species." Earlier in tlie year 

 also, at the Loffodens, he obtained several kinds of 

 floating fish ova, some of wliich he succeeded in hatch- 

 ing; but he could not speak with certainty as to all the 

 species. In his published reports, however, he men- 

 tions the gurnard {Trigla) as one of the fishes whose 

 floating ova he had identified. 



Entirely subversive as these discoveries of Professor 

 Sars are of our popular notions about fish-spawning, it is 

 even more unexpected to find that both he and M. A. 

 W. Malm, of Grothenburg, have independently ascer- 

 tained that the ova of the plaice (Pleuronectes platessa) 

 follow tliis same rule of floating at the surface ; and 

 M. Sars adds that it undoubtedly applies also to the 

 other Pleuronectido3. 



It is evident then that the floating of fish ova during 

 the development of the embryo is not so exceptional as 

 it appeared to be at the beginning of M. Sars' investi- 

 gations ; but that there is good reason for believing it 

 to be the general rule in several distinct fomilies of sea 

 fish ; whilst, as M. Sars points out, the development 

 takes ])lace at the bottom in the case of those fishes 

 especially whose ova are cemented together by a 

 glutinous secretion, or fastened in lumps to foreign 

 bodies, such as Alg;u, Ilydroids, c^c. lie mentions as 

 examples among others in which the latter mode is the 

 rule, the herring (Cluj^ea), the Capelan {Os7nerus), the 

 species of Cotdis, Liparls, &c. 



It is particularly worthy of notice that, according 

 to these observations of the Norwegian natuialists, all 

 the important kinds of fish taken by our line fishermen 

 and trawlers, and the mackerel among such as are 

 caught by the drift-nets, may be reasonably included — 



