340 DR. p. p. CARPENTER ON THE SHELLS OP PANAMA. [June 23, 



preservation of types therefore, and the interchange of specimens 

 named from types, is of the first importance to save the time and 

 ensure the accuracy of succeeding writers. The Smithsonian Insti- 

 tution has fully recognized this principle by directing that the first 

 available duplicate of all type species described from its collections 

 shall be deposited in some museum open to students on the other 

 side of the Atlantic. 



As the authorities of Amherst College had not taken any steps 

 to figure their unique specimens, and as Prof. Adams's determina- 

 tions of old species had not been verified, I made it my business 

 (when visiting America to deposit the first duplicate series of the 

 Mazatlan Shells in the New York State Museum at Albany) to com- 

 pare Prof. Adams's collection, on the spot, with his published book, 

 in my copy of which I made my notes and sketches at the time. 

 Every facility was afforded me by the Curator. I was allowed freely 

 to handle the specimens in the presence of his assistant, and to draw 

 the minute species under my microscope*. I took with me for com- 

 parison the drawings of the minute Mazatlan shells in the British 

 Museum. The species being numbered in both the Panama and the 

 Mazatlan lists, it is easy now to institute a comparison between them. 

 They are here distinguished by the initials P. and M. 



P. 1. Ovula avena. IMay be distinct from Radius variabilis, 

 M. 435, being much more stumpy, with a thicker lip ; but the few 

 specimens are in poor condition, and the differences may be accidents 

 of station. 



2. Ovula emarginata= Car inea e. Quite distinct from its Carib- 

 bean analogue C. gibbosa. 



3. Ovula neglecta, C. B. Ad., is probably a small variety of Ra- 

 dius variabilis. 



4. Ovula variabilis, C. B. A.d.=Radius v., M. 435. 



5. Ovula, sp. ind., Tprohahly =variabilis, jun. 



6. Cyprcea arabicula= Aricia a., M. 438. 



7. Cyprcea cervinefta=C. exanthema, M. 436. Having now 

 examined a multitude of specimens from different stations on the 

 west coast, which differ from each other quite as much as they do 

 from the typical Caribbean forms, I am confirmed in the belief of 

 their identity. 



8. Cyprcea punctulata=- Aricia p. Erroneously given, in M. 

 p. 374, as a probable synonym of A. arabicula. It is less thickened 

 at the sides, with smaller spots. Although specimens of arabicula 

 graduate into it at the back, it may always be known by the mouth, 

 which has its teeth much further apart. 



9. Cyprcea pustulata=Trivia p., M. 439. 



* The week which this work occupied was spent with the widow of the late 

 Professor, who undertakes the duty of boarding students. Her two oldest sons 

 were, alas ! among the early victims of the civil war. 



