20 



2. CYRENA FLORIDANA, Conrad. 



Smithson. Monogr. 

 Tampa bay. (Ex auctore.) 



a. Saracota bay. 



b. Boca Saca pass, Florida. 



c. Cyrena protexta> Conrad. Tampa bay. (Ex auctore.) 



3. CYRENA MEXICANA, Sowerby. 



Smithson. Monogr. 

 San Bias. 



a. Panama. 



b. Mazatlan. 



c. Cyrena fragilis ', Deshayes. Mazatlan. (Ex auctore.) 



d. Cyrena in&quilateralis y Deshayes. Mazatlan. (Ex auctore.) 



4. CYRENA OLIVACEA, Carpenter. 



Smithson. Monogr. 

 Mazatlan. (Ex auctore, fide Cuming.) 



5. CYRENA GERMANA, Prime. 



Ann. N. Y. Lyceum VIII. 

 Panaco river, near Tampico, Mexico. 



6. CYRENA TRIANGULA, v. d. Busch. 



Smithson. Monogr. 

 Tamatico river, Mexico. 



