xil INTRODUCTION. 
During recent years, however, shortly after having commenced the publication of 
this work, I have from time to time received for determination specimens of Costa 
Rican land and freshwater shells from Henry Pirrrer and Pierre BIoLiey, both 
residents in San José. These men have paid remarkable care and attention to the 
Mollusca, even to the very minute forms, and they have succeeded in rendering the 
conchological fauna of this country one of the best known within Central America. 
H. Pittier, first employed at the observatory in San José, and subsequently appointed 
a member of the Physical and Geographical Institute of that republic, commenced to 
send me shells in 1890, and then nearly every year afterwards, until the unexpected 
suppression of that Institute in January 1899, due to change of government. 
P. Biolley, of Neufchatel, Professor and at present Assistant Naturalist at the Museo 
Nacional of Costa Rica, since 1891 resident in that country, sent his shells to his old 
teacher P. Godet, Director of the Natural History Museum at Neufchatel, from whom 
I had most of them for determination and comparison. He has written a small 
pamphlet entitled ‘ Moluscos terrestres y fluviatiles de la Meseta Central de Costa Rica’ 
(San José, 1897), in which fifty-nine species are enumerated. 
PANAMA. 
Up to the present time nothing but a few stray notes on the land and freshwater 
Mollusca of the State of Panama have been published, the earliest being those relating 
to H. Cuming’s collections, made in 1827 and the following years. The marine and 
submarine shells have, on the contrary, been thoroughly investigated by C. B. Adams 
[see ‘ Annals of the Lyceum of Natural History of New York,’ v. (1852), and also 
Carpenter’s work], who has given a special list of those collected by himself, with 
accurate particulars of the localities of each species. The submarine Mollusca, 
therefore, of the shores of the Bay of Panama are better known than those of any 
other place in Central America or Mexico, either on the Pacific or the Atlantic 
coast. 
A few shells obtained in Veraguas by Warscewicz, about 1856, are preserved in the 
Berlin Museum. | 
For the knowledge of some additional terrestrial forms I am indebted to G. C. 
CuamPion, who collected in Chiriqui, in 1881-83. 
