GASTROCOPTA, AFRICA. 123 



scribed as races of barbadensis. A somewhat more synthetic 

 view than I have taken would unite pellucida and barbadensis 

 through the several races of each ; but so long as they are kept 

 as separate species, acarus also may stand. In islands so ex- 

 cessively arid as the Cape Verdes, it seems rather unlikely 

 that an Antillean species would be imported and spread almost 

 a]l over the archipelago. 



The angulo-parietal lamella is formed as in B. servilis, there 

 being a lobe directed towards the periphery at the junction 

 of the angular and parietal portions (pi. 22, fig. 10). The 

 upper columellar fold alluded to by Benson is really an infra- 

 parietal, " being absent, or sometimes just represented by an 

 extremely minute and scarcely perceptible, very deeply im- 

 mersed, rounded tubercle," as Wollaston has noted. The 

 columellar lamella is stout and horizontal throughout, rather 

 short. The upper palatal plica is stout and short, the lower 

 strong, long, and entering; basal plica rather small, tuber- 

 cular. The well-reflected peristome is distinctly but not 

 greatly thickened within, and of a cinnamon-buff color. As 

 usual the thickening disappears at the upper curve of the lip. 

 A rather thick parietal callous connects the converging ends 

 of the lip. The color is very pale cinnamon-buff, sometimes 

 transparent enough to show the axis faintly through the last 

 whorl. Striation is extremely faint. There is no noticeable 

 crest behind the lip. Length 1.95, diam. 0.9 mm. ; 4% whorls. 



This species is the type of the genus Gastrocopta. It has 

 not been figured before, and its affinity to Antillean species 

 has not been noticed. 



69. GASTROCOPTA MICROBUS (Dautzenberg). PI. 22, fig. 9. 



Shell small, umbilicate, subpellucid, rather thin. Spire ele- 

 vated, turrited, suture deep. Whorls 5, above a little de- 

 pressed, then strongly convex, obliquely very finely striatu- 

 late. Aperture rounded, the peristome continuous, expanded, 

 4-toothed; one strong parietal fold, one minute columellar, 

 two in the right margin, the upper one rather short. Color 

 dirty corneous. Length 2, diam. 1 mm.; aperture % mm. 

 high, % wide (Dautzenberg}. 



