22 



BULLETIN 90, UNITED STATES NATIONAL MUSEUM. 



Chione (Chatnelea) rhodia Dall. 

 Anomalocardia floridana Conrad. 

 Venus halidona Dall. 

 Tellina segregata Dall. 

 Tellina chipolana Dall. 



* Tellina dira Dall. 



Tellina {Macaliopsis) merula Dall. 

 Tellina (Merisca) halidona Dall. 



* Tellina (Angulus) atossa DaW. 



Macoma irma Dall. 



* Semele sardonica Dall. 

 Scmele silicata Dall. 



Corbula (Cuneocorbula) burnsii Dall. 

 Corbula (Cuneocorhula) sarda Dall. 



* Corbula (Cuneocorbula) kaghriana 

 Dall. 



Panope whitfieldi Dall. 

 Gastrochwna rotunda Dall. 



FORAMINIFERA. 



Orbitolites floridanus Conrad. 



SYSTEMATIC ARRANGEMENT. 

 GASTROPODA. 



Order PULMONATA. 



Family HELICIDAE. 



Tribe BELOGONA. 



Genus CEPOLIS Montfort. 



Cepolis Montfort, Conch. Syst., vol. 2, p. 150, 1810. Type, Helix cepa 

 Muller (Haiti). 



Subgenus PLAGIOPTYCHA Pfeiffer. 



Plagioptycha Pfeiffer, Mai. Blatt., 1856, p. 135. — Martens in Albers, Die 

 Heliceen, ed. 2, p. 145, 1860. Type, Helix loxodon Pfeiffer (Balianias). 

 Plagioptycha Pilsbry, Man. Conch., vol. 9, p. 185, 1894. 



Doctor Pilsbry considers this group as nearest to the ancestral 

 forms from which the modern subdivisions of the genus have arisen. 



In Oligocene times (formerly referred to as Miocene or Old Mio- 

 cene) this group was abundantly represented on the group of islands 

 which represented the nucleus of the present Floridian peninsula. 

 It apparently became extinct in Florida with the lowered tempera- 

 ture of the Miocene epoch, though still represented farther south in 

 the Bahamas, Cuba, and Haiti by an abundance of recent species. 



CEPOLIS (PLAGIOPTYCHA) LATEBROSA Dall. 



Plate 2, figs. 13, 17, 19. 



Helix (Jeanneretia) latehrosa Dall, Trans. Wagner Inst., vol. 3, pt. 1, p. 

 8, pi. 1, figs. 8, 8a, Aug., 1890. 



Tampa silex beds, Dall and Post. Only a single specimen was ob- 

 tained. U. S. Nat. Mus. No. 111944. 



