326 8. Abstammungslehre. 



eyes and the shade of coloration are not determined by either locality or size 

 of the specimen. The lighter colored the specimen the more degenerated the 

 eyes. The more degenerated the eyes the greater the negative phototropism, 

 and vice versa. Humidity is a stronger factor than negative phototropism 

 in determining the location of specimens in the experimental tubes. Change 

 of relative humidity is fatal in a few hours. Lillie (Chicago). 



897) CrOTlgh, L. H., A monograph of the Tapeworms of the Sub- 

 family Avitellinae, being a revision of the genus Stilesia, and 

 an account of the histology of Avitellina centripunctata. 



(Quart. Journ. Micr. Sc. 56,2. p. 317—385. 3 plates. 1911.) 



Doncaster (Cambridge). 



898) Schmidt, J. (Copenhagen), Biology of the Eel-fishes, espe- 

 cially of the Conger. 



(Nature 86,2158. p. 61—63. 1911.) 



Describes the results obtained during the Atlantic and Mediterranean 

 cruises of the steamer "Thor" (winter 1908 — 9, summer 1910) with regard to 

 the egg-laying and larvae of Eels, especially the Conger. The conclusions 

 are that eels spawn at great depths, in the most central parts of the ocean- 

 basins, but whether at the bottom or not is not known. The eggs occur pe- 

 lagically near the surface, and there give rise to the pre-leptocephalous stages, 

 which are found near the surface over deep water. The Leptocephali also 

 occur near the surface, sinking lower during the day, but they spread more 

 widely and are found also over shallower water. Some species during meta- 

 morphosis sink to greater depths, but the conger and common eel remain 

 during the greater part in the upper layers. Doncaster (Cambridge). 



899) Nichols, J. T., Observations on Birds and Fishes Made on an 

 Expedition to Florida Waters. 



(New York Academy of Science, Section of Biology. 10. April 1911.) 



This paper concerned itself with a trip through Florida waters on 

 Mr. Alessandro Fabbri's yacht „Tekla" in the interests of the American 

 Museum's Department of Fishes. 



Attention was called to the abundance of the White Ibis and Louisiana 

 Heron, contrasted with the scarcity of aigrette-bearing Herons. After a brief 

 mention of the work and the results obtained, the balance of fish-life in a 

 fresh water outlet of the everglades was compared with the balance of fish 

 life in the salt water as at Key West. 



In the former situations Gar pikes (Lepisosteus) were abundant, as 

 were various Centrarchids (among them the large-mouthed Bass and Blue-gill 

 Sunfish) which darted in and out through the little Channels among the weed, 

 but which did not drive head first through the masses of weed as did the 

 leathery skinned Gars, and only made quick sallies into the shallower and less 

 open waters, where various species of Pceciliids, especially Gambusia, and 

 Fundulus goodei were tremendously abundant. The surprising freedom 

 from mosquitoes was mentioned and it was pointed out how the existing 

 balance of fish life was favorable to a great abundance of Gambusia etc. 

 which might be expected to prey on mosquito larvse. The centrarchids would 

 be likely to hold in check a fish like the Banded Pickerei, which would have 

 f'ollowed these small fishes into the shallows where the Centrarchids did not 

 follow them, and perhaps materially reduced their numbers. The Situation 

 here where the large primative gar, the spiny rayed modern Centrarchids, and 

 the abundant intermediate Pceciliids made up the bulk of the fish population, 

 was composed with the more complicated marine Situation where large 



