2 nR. p. p. CARPENTER ON THE SHELLS OF PANAMA. 



preservation of types tlierefore, and the interchange of specimens 

 named from type*, is of tlie first importance to save the time and 

 ensure tlie acenracv of succeeding writers. The Smithsonian Insti- 

 tut inn has fnllv recojinized this principle by directing that the first 

 avnilal)ie duplicate of all type species described from its collections 

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

 side of tiie Atlantic. 



As the authorities of Amherst College had not taken any steps 

 to figure their tuiicpie specimens, and as Prof. Adams's dctermina- 

 t'.ons of old sjiecies had not heen verified, I made it my business 

 (^wlien visitnig 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 sketclu-s 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 forcom- 

 ])arison the drawings of the minute ^lazatlan sliells in the British 

 Museum. The species being numbered in both the Panaii:a 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. Orula avena. May be distinct from Radius vnrinhilis, 

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

 8j)ecimens are in poor condition, and the differences may be accidents 

 of station. 



2. Oiuila einnr(/innfa = Caruiea e. Quite distinct from its Carib- 

 bean analogue C. yibbosa. 



3. Oim/a neylecta, C. B. Ad., is probably a small variety of Ra- 

 dius variubtlis. 



•J. Oi'ula variabilis, C. B. Xd. = R'i(/ius v., M. 435. 



5. Ocula, sp. ind., probably = raWai///*, jun. 



6. Ci/pnea arnbicula= Aricia a., M. 438. 



7. Ci/preea cervinetta=C. exanthema, M. 436. Having now 

 examined a multitude of sjiecimens from ditFerent 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. arabieida. It is less thickened 

 at the sides, with smaller spots. x\lthoagh specimens of urabicnla 

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

 wiiich has its teeth much further apart. 



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

 I * 176 



