MOLLUSC A OF PORTO RICO. 
435 
Family CYCLOSTOMATI 1)45 
Genus CHOANOPOMA Pfeiffer. 
Choanopoma decussatum Lamarck. 
Cyclostoma decussofa Lamarck, An. sans Vert., VI, p. 147, 1822. 
Porto Rico, many localities (Crosse). 
Choanopoma senticosnm Shuttleworth. 
Cyclostoma {Choanopoma) senticosum Shnttleworth, Diagn.nene Moll., Berner Mitth., 1854, p.90. 
Porto Rico; Isle of Vieques (Crosse). 
Choanopoma sulculosum Pfeiffer. 
Cyclostoma sulculosum (F6russac ms.) Pfeiffer, in Conch. Cab., Cyclostoma, p.313, pl.xni, figs. 15-17, 1863. 
Isle of Vieques; St. Bartholomew (Crosse). 
Genus CISTULA Gray, 1850. 
Cistula riisei Pfeiffer. 
Cistula riisei Pfeiffer, Mon. Pneum. Viv. , p. 417, 1852. 
Porto Rico, several localities (Crosse). 
Cistula aguadillensis Pfeiffer. 
Cistula aguadiUensis Pfeiffer, Mal.Bliitt., xxn, p.207, 1875. 
Aguadilla; Penuelas, Porto Rico (Crosse). 
Cistula lineolata Lamarck. 
Cyclostoma lineolata Lamarck, An. sans Vert., iv, p. 147, 1822. 
Puerto Rico (Crosse). 
Genus CH0NDR0P0MA Pfeiffer, 1847. 
Chondropoma terebra Pfeiffer. 
Chondropoma terebra Pfeiffer, Mal.Blatt., VIII, p.74, pl.Ii, figs. 4-6, 1861. 
Sierra Morales, Porto Rico (Crosse). 
Chondropoma blauneri Shuttle worth. 
Cyclostoma (Chondropoma) blauneri Shuttleworth, Diagn.neue Moll., Berner Mitth., 1854, p. 91. 
Humacao, Porto Rico (Crosse). 
Chondropoma swifti Shuttleworth. 
Cyclostoma (Chondropoma) swifti Shuttleworth, Diagn.neue Moll., Berner Mitth., 1854, p. 91. 
Near Ponce, Porto Rico (Crosse). 
Chondropoma newtoni Shuttleworth. 
Cyclostoma (Chondropoma?) newtoni Shuttleworth, Diagn.neue Moll., Berner Mitth., 1854, p..92. . 
Near Arecibo, Porto Rico (Crosse). 
Family TRUNCATELL1D45 
Shell cylindrical, truncated in an adult state; aperture entire, oval; peristome continuous, thick- 
ened; operculum oval, paucispiral, its nucleus excentric. 
Genus TRTJNCATELLA Risso, 1826. 
Shell with longitudinal ribs, shining; operculum horny. 
Type, T. truncatula Draparnaud. 
