STREPTAXIS. 69 



present form has a higher, more conical spire and is less oblique, 

 and with more flattened base. 



S. ALVEUS, Dunker. PI. 27, fig. 11 ; PI. 12, fig. 29. 



Shell perforate, regular!} 7 obliquely finely costulate above, 

 planate and smooth beneath; whorls 10, flattened, the last 

 obtusely angulated at the periphery ; corneous white ; lip ex- 

 panded, narrowly reflected below. Diam., 10 mill. 



Brazil. 



Helix contermina, Reeve (fig. 29), is a synonym. 



S. DESHAYESIANUS, Crosse. PI. 14, fig. 97. 



Narrowly umbilicated, corneous white; whorls 6^, witli im- 

 pressed striae above, the base planulate, inconspicuously striate, 

 somewhat shining ; lip white, reflected, subflexuous and thinner 

 above. Diam., 5*mill. 



Brazil. 

 S. TURBINATUS, Morelet. PI. 12, figs. 24, 25. 



Perforate, thin, corneous white ; whorls 6, convex, suture 

 profound, regularly costulate, base planulate ; lip regularly 

 expanded, shortly arcuate above. Diam., 10 mill. 



At Lake Quilonda, Angola, W. Africa. 



S. DEPLANATUS, Pfr. PL 14, figs. 84-86. 



Rimately subperforate, thin, diaphanous, yellowish ; whorls 6^, 

 closely costulately striate above ; base somewhat flattened, 

 smooth, shining ; lip white, narrowly expanded, reflected. 



Diam., 11-3 mill. 



Habitat unknown. 

 S. WELWITSCHI, Morelet. PI. 14, figs. 73-75. 



Concavely rimate, thin, smoothish, plicately striated at the 

 sutures, shining, semidiaphanous, light yellowish ; whorls 5J, 

 suture deep, base of shell planulate, smooth ; lip white, thin, 

 expanded. Diam., 13 mill. 



Cazengo, Angola, W. Africa. 



8. PROSTRATUS, Gould. PL 27, fig. 9. 



Perforate, rather thin, hyaline white; whorls 5J, lightly 

 arcuately striate above, smooth below, the last whorl subangu- 

 late at the periphery in front ; parietal wall edentulous or with 

 a minute tooth; lip slightly reflected. Diam., 10 mill. 



Cape P almas, W. Africa. 



