GASTROCOPTA, NORTH AMERICA, WEST INDIES. 77 



tinctly bifid angulo-parietal lamella with a small projection 

 on the eolumellar side, seen in a basal view, the absence of any 

 crest behind the lip, which while slightly thickened within 

 has no distinct white or brown callous, and the rather short 

 lower palatal plica. 



It differs from G. servilis by the smaller size, especially the 

 smaller diameter; this dimension varying within narrower 

 limits than the length. G. barbadensis has the angulo-parietal 

 lamella much more distinctly bifid, in a front view of the 

 aperture; the lower palatal plica is longer and more deeply 

 placed; and when typically developed, the teeth are larger 

 than in pellncida. 



Typical pcllucida is before me from La Guira, S. Diego, 

 El Abra, Viiiales, Sierra de S. Vicente (1.7x0.75 mm.), all 

 from the John B. Henderson collection, and from some other 

 Cuban localities. Specimens from Jamaica, Port Henderson 

 (Swift coll.) and Mandeville (A. P. Brown), are entirely 

 typical. In the Biniini group of the Bahamas it occurs at 

 South Bimini Cay (length 2.1 to 2.3 mm.) and north end of 

 South Cat Cay, both collected by Geo. H. Clapp, 1912, the 

 shells vary from typical size to somewhat larger. 



Variation may be noted as follows : 



a. Typical in size or larger, the angulo-parietal lamella not 

 showing any projection on the eolumellar side, or with it 

 scarcely noticeable. Cuba: San Juan de Letran, near Trini- 

 dad, the largest 2.15 x 0.9 mm., and El Vedado, Havana (Pils- 

 bry). Teneria de Guane; Costanera del Abra, Pinar del Rio; 

 Cabanas Light, and Laguna de Piedra (Henderson). Haiti: 

 Charmettes and St. Mark (Henderson and Simpson). Vieque. 

 Also Antigua, state of Vera Cruz, Mexico (S. N. Ehoads), 

 the largest one 2.2 mm. long, 0.95 wide. 



b. Lots from Costanera de S. Vicente, Guane, and Mogote 

 de la Mina, Consolacion del Norte, are more or less interme- 

 diate between the typical form and the variety a. 



c. One lot from Ponce, Porto Rico (R. Swift) has a small 

 crest behind the lip, and the color is pale brownish. It differs 

 in no way from the continental hordcacella. 



