78 GASTROCOPTA, NORTH AMERICA, WEST INDIES. 



22a. G. pellucida form biminiensis, n. f . PL 15, figs. 11, 12, 13. 



The shell is dark brown, having a crest or trace of it behind 

 the lip; lip widely reflected and moderately thickened, but 

 not nearly so thick as that of crassilabris. Angulo-parietal 

 lamella nearly straight and not bifid, resembling that of B. 

 pellucida. No buttress under the columellar lamella. 



Length 2, diam. above aperture .9 mm.; 43/4 whorls (type). 



Length 2.15, diam. above aperture .9 mm. ; 5 whorls. 



Bimini Islands: north end of South Cat Cay and South 

 Bimini Cay, type locality (Geo. H. Clapp). 



In a series from Rosario, Cuba (Henderson), the lip is a 

 little thicker than usual in pellucida, about as in form bimini- 

 ensis. The angulo-parietal lamella is nearly straight and 

 simple in some individuals (pi. 15, fig. 10; length 1.6, diam. 

 0.75 mm.) ; but in others the angular and parietal lamellae are 

 not in alignment, the tooth in basal view resembling that of 

 crassilabris, pi. 18, fig. 9. The figured shell of this kind 

 measures, length 1.8, diam. 0.8 mm. (pi. 15, fig. 7). The 

 smallest shell in this lot is 1.5 mm. long (fig. 10). 



22b. G. pellucida delicata n. subsp. PL 15, figs. 4, 9. 



The shell is smaller, very thin and fragile, slightly paler 

 than marguerite yellow, without a crest behind the thin lip. 

 The angular lamella is very weak and low, the parietal and 

 columellar lamellae moderately developed. Basal fold want- 

 ing, or very minute when present. 



Length 1.55, diam. above aperture 0.7 mm. ; 4% whorls. 



Length 1.36, diam. above aperture 0.65 mm. ; 4 whorls. 



Distribution. North end of South Cat Cay, Bimini group, 

 Bahamas (Geo. H. Clapp, May, 1912). Cotypes in collections 

 of Clapp, A. N. S. P., and J. B. Henderson. 



This very minute and fragile form contrasts with the sub- 

 species biminiensis of the same islands, and both seem well 

 differentiated from pellucida. 



22c. G. pellucida hordeacella (Pilsbry). PL 17, figs. 1 to 4; 



pi. 16. 

 This continental race differs from pellucida by having a 



