On the Embryology of the Retina of Teleosteans. 263 



latter name has the priority of date, and of the two localities 

 given for the species, viz., India and New Holland, tlie second 

 is no doubt erroneous. 



The Fabrician species Lamia rotator [Moaohammus 

 rotator of the Munich Catalogue) is, as I find from the tjpe 

 in the Banksian Cabinet, identical with the North- American 

 species Goes tigrinus, Degeer. The locality — India or. — 

 given by Fabricius, is of course wrong. As both descriptions 

 — the Fabrician and that of Degeer — appeared in the same 

 year, it is doubtful which has priority of date. Degeer's 

 name being better known, and his description being fuller 

 and accompanied by a figure, tliere is no reason why it should 

 not be retained, and the Fabrician name sunk into a synonym. 



XXXY. — Researches at the St. Andrews Marine Laboratory 

 (lender the Fishery Board for Scotland). — On the 

 Embryology of the Retina of Teleosteans. By Dr. R. 

 Marcus Gunn, M.A., M.R.C.S., Surgeon to Moorfields 

 Hospital, London. 



In the investigations hitherto made on the development of 

 the eye in the bony fishes the ova of freshwater forms have 

 been employed. I am indebted to Professor M'Intosh, 

 F.R.S., tor an opportunity of examining carefully prepared 

 sections of embryos of marine Teleosteans, which he had 

 succeeded in maturing in the St.-Andrews Marine Labora- 

 tory. 



Several causes combine to render accurate results more 

 difficult of attainment in the case of fish than in other in- 

 stances where ova can be watched during maturation. Not 

 only do the ova of fish vary much in the rapidity with which 

 they mature after impregnation in different genera and species, 

 but even in the same species, according to external conditions 

 especially the temperature of the water. Indeed, Professor 

 M'Intosh tells me that in the same series of ova, matured 

 under identical conditions, some individuals develop more 

 quickly than others. Great diversity, moreover, obtains in the 

 stage of development attained before hatching in different 

 fish, and even to some extent in different individual ova of 

 the same fish. 



I have consequently been obliged to base my calculations 

 of advance in development simply on histological features 



