PROCEEDINGS OF THE ACADEMY OF [Jan., 



COSTA RICAN LAND AND FRESHWATER MOLLUSKS. 

 BY HENRY A. PILSBRY. 



The moUusks enumerated below were collected by Dr. Philip P. 

 Calvert and Mrs. (Amelia S.) Calvert in the year of their residence 

 in Costa Rica, from May, 1909, to May, 1910.' As their chief 

 object was to study life histories and transformations of tropical 

 dragonflies, other material was taken only when encountered in 

 the course of this pursuit. 



Much of their field work was done in districts where Prof. Paul 

 Biolley^ and H. Pittier had collected shells, yet some eight species 

 new to Costa Rica were found, five of them new to science. This 

 large proportion, in a total of 28 species taken, is evidence that our 

 knowledge of the fauna is still very incomplete, though as von 

 Martens remarks, it is "one of the best known within Central Amer- 

 ica." 



Biolley has carefully recorded the elevation of localities where 

 he collected shells, and some additions to this subject are now made; 

 but on tabulating the data it appears that so many species are known 

 from few localities, or but one, that conclusions as to zonal dis- 

 tribution would be too crude to have value. Some species have a 

 wide vertical range; the apparent restriction of others in the same 

 districts may probably be due to deficient collecting. 



Costa Rica is known as farthest north for a number of character- 

 istically South American genera, such as Lahyrinthus, Solaropsis 

 and Marisa. The Brazilian genus Uncancylus, now reported, is 

 an interesting addition to this series. 



^ Calvert, Amelia S. and Philip P. A Year of Costa Rican Natural History 

 New York. The Macmillan Company, 1917. Besides details as to the locali- 

 ties where collecting was done, this interesting book contains a map and a bib- 

 liography of Costa Rican natural history, and related subjects. 



2 B'oiley, P. Moluscos terrestes y fluviatiles de la meseta central de Costa 

 Rica. San Jose. Tipografia Nacional, 1897. Fifty-nine species are listed, 

 with localities and comments. 



The material collected by Biolley and Pittier was determined and the new 

 forms described by Professor E. von Martens in his fine volume on land and fresh- 

 water mollusks in the Biologia Centrali-Americana, 1890-1901. 



