78 SUBULINA, WEST AFRICA. 



striatella to become obsolete or irregular [these specimens are 

 S. angustior, H. P.], while in Lea's specimens it is quite uni- 

 formly even and regular throughout. I should be disposed to 

 regard the two shells as varieties of the same species. ' ' 



Var. petrensis Morelet. 



Slightly less lengthened and a little more ventricose than 

 typical striatella, making the shell more conic; also thinner, 

 more transparent, engraved with less pronounced striae ; of a 

 yellowish-fawn tint. Length 16, diam. 5 mm, (Morel.). 



Freetown, Sierra Leone (Dr. Welwitsch). 



There are 9 to 10 whorls, the last less than a third the total 

 length, and obtusely angular. It was originally described as 

 a distinct species, but subsequently united to striatella by 

 Morelet. It probably is a distinct as 8. vivipara and some 

 of the other closely related continental forms. 



5. S. CEREA (Pfeiffer). PI. 11, fig. 88. 



Shell oblong-turrited, thin, finely and regularly striate, 

 glossy, pellucid, pale wax-colored. Spire rectilinear, the apex 

 obtuse, suture moderate, minutely crenulate. Whorls 8, 

 slightly convex, the last scarcely more than one-fourth the 

 total length, subangular below the middle. Columella curved, 

 abruptly truncate. Aperture oblique, oblong ; peristome sim- 

 ple, unexpanded, the right margin lightly arcuate. Length 

 14, diam. 4.66, aperture 4 x 2.5 mm. (Pfr.). 



Fernando Po (Fraser). 



Achatina cerea PFR. P. Z. S. 1852, p. 86 ; Conchyl. Cab. p. 

 338, pi. 37, f . 5-7 ; Monogr. iii, p. 501. 



This form seems to be a little wider than 8. striatella. Dr. 

 Boettger reports it from Bibundi, Kamerun, and Gabun 

 (Nachrbl. 1905, p. 178) . 



6. S. ANGUSTIOR (Dohrn). PI. 11, figs. 96, 98 to 101. 



Shell turrited-subulate, rather solid, slightly glossy, waxen, 

 longitudinally closely striate, the strice slightly oblique; apex 

 rather obtuse. Whorls 8 to 9, nearly flat, the last -one-fifth 

 the length, angular in the middle. Columella arcuate, ob- 



