NOTES AND MEMORANDA. 623 



Echinorhinus spinosus, Blain. 



The distribution of the spinous shark seems to be extensive, from 

 the North Cape to the Cape of Good Hope, but it is not a common 

 visitor to the shores of Britain, nor indeed anywhere. Day mentions 

 over twenty records of its appearance, spread over some sixty years, 

 and most of the specimens were obtained on the south coast. Stead 

 {Jour. 31. B. A., vol. iv. p. 264) gives a description of a further sample 

 captured in 1895. A female specimen, 7 feet long, and about 5 cwt. in 

 weight, was caught in the beam-trawl off the Eddystone, on the 28th 

 November, 1902. 



Hybridism in Marine Fishes. 



The possibility of hybrids occurring amongst sea fishes has been 

 displayed by various naturalists, of whom Mr. Thomas Scott may 

 be more particularly mentioned. Whilst working on the Garland on 

 the east coast of Scotland some twelve years ago, Scott succeeded 

 in fertilising the eggs of several species by the milt of others. The 

 conditions on board were not favourable to the success of the experi- 

 ments ; the embryos died before hatching. One lot of eggs, however, 

 of brill crossed with the turbot, was sent to the St. Andrews Marine 

 Laboratory,* and the young larvae hatched out there, and seemed as 

 strong and healthy as normal larvse reared in aquaria. 



The probability that hybrids actually occur in the adult condition 

 is a much more difficult matter to determine. At different times 

 supposed hybrids have been examined, only to be rejected, and but 

 few examples have stood the test of scrutiny. According to Giinther, 

 a fish obtained at Bristol, the skin of which is in the national 

 collection, may have been a cross between a shad and a pilchard, 

 and another example in the same collection a cross between the two 

 shads, f A nearer approach to certainty, with respect to the shads, 

 has been attained by Hoek,;J: who has made a statistical investigation 

 of the characters of supposed crosses between the two shads of the 

 Ehine. The characters are intermediate between the two species, and 

 reasoning from this fact, as well as from the possibility of cross- 

 fertilisation whilst the fish are spawning on the same or neighbouring 

 grounds, Hoek is inclined to believe that the forms he describes are in 

 reality hybrids. 



In this case the species are nearly allied, and for the most part live 

 in fresh water, where hybridisation had already been shown to occur. 



* W. C. Mcintosh, Ann. Rep. Scottish Fishery Board, ix., p. 317, Plate XIII. 

 t Day, British Fishes, vol. ii., p. 238. 



t "Neuere Lachs- unci Maifisch-Studien," Tijd. Nederl. Dierkundige Vereenig. (2), 

 vol. vi., p. 3, 1899. 



