NOTES ON THE OCCURRENCE OF THE CRUSTACEAN ALO- 

 NOPSIS IN AMERICA, WITH DESCRIPTION OF A NEW 

 SPECIES. 



By Alfred A. Doolittle, 



Of the Central High School, Washington, District of Columbia. 



The presence of a genus of fresh-water Entomostraca belonging to 

 the order Cladocera, the genus Alonopsis, does not seem to have been 

 recorded hitherto in America. A species from Wisconsin described 

 as Alonopsis media Birge * is now regarded as a variety of Alonopsis 

 latissima Kurz.^ Alonopsis latissima has been collected in almost all 

 parts of the United States and in South America,^ as well as in the 

 Eastern Hemisphere, but the species has been removed from the 

 genus Alonopsis and the genus Pseudalona Sars^ erected for it. 

 Thus no true Alonopsis remains on record for America. 



It has, therefore, been a matter of interest to find two species of 

 Alonopsis in the course of determining the food of young fishes of 

 New England lakes. While investigating the Entomostracan plank- 

 ton of Sebago Lake, Maine, under the direction of the United States 

 Bureau of Fisheries, small-mouthed black bass, Micropterus dolmieu, 

 38 to 48 mm. long, when taken from a certain locality were found to 

 have eaten as part of their food two species of this genus, namely, 

 Alonopsis elongata Sars on July 25, 1906, July 31, 1906, and August 

 16, 1908, and also Alonopsis aureola on July 25, 1906. This second 

 species is new, and is hereinafter described. Similarly, Dr. W. C. 

 Kendall, of the United States Bureau of Fisheries, in his investiga- 

 tions of the Salmonidse of Sunapee Lake, New Hampshire, captured 

 a few specimens of the Sunapee golden trout, Salvelinus aureolus, 27 

 and 28 mm. long, on April 23, 1910. These have been examined by 

 the writer for their food, and there appeared also in their stomachs 

 Alonopsis aureola. 



1 E. A. Birge. Notes on Cladocera. Transactions of the Wisconsin Academy of Sciences, Arts, and Let- 

 ters, vol. 4, 1876-1877 (1879). 



2 Herrick and Turner. Copepoda, Cladocera, and Ostracoda of Minnesota. Geological and Natural 

 History Surrey of Minnesota, Second Report of the State Zoologist for 189.3 and 1894. Zoological series, 

 vol. 2, 1895. 



3 G. O. Sars. Contributions to the Knowledge of the Fresh-water Entomostraca of South America as 

 shown by Artificial Hatching from Dried Material. Archiv Math. Nat. Kristiania, vol. 23, 1901, No. 3. 



Proceedings (J. S. National Museum, Vol. 43— No. 1940. 

 48702°— Proc.N.M. vol. 43—12 36 561 



