-16 PSEUDACHATINA. 



or less distinctly angular, the angle disappearing near the 

 aperture. Aperture oblique, rounded-oval, whitish or whitish- 

 fleshy inside, slightly pearly, the external basal brown zone 

 showing through below. Columella compressed, twisted in- 

 ward, very obliquely truncate, white. Peristome narrowly 

 reflexed or reflexed-spreading, somewhat thickened, always 

 white; margins joined by a whitish callous, which is thick- 

 ened and opaque towards the columella, transparent towards 

 the outer lip. Length 47.5 to 75, diam. 25 to 33, alt. apert. 

 20 to 31 mm. (d'Ailly). 



West Africa: Kamerun , at Etome (Dusen), and Itoki 

 (Dusen, Sjostedt). 



P. martcnsi d'Ailly, Bihang, etc., p. 95, pi. 4, f. 7-9 (1896). 



Resembles P. wrigliti var. buchncri in general appearance 

 and system of coloration. The basal zone does not extend to 

 the angle of the whorl. It is more sharply limited above than 

 in any other species, and has the same appearance at all ages 

 of the shell (see fig. 32, base of an immature specimen). In 

 adults the shell is solid and thick ; in the young thin and semi- 

 transparent. The embryonic shell has a noticeable umbilical 

 perforation, which lasts in the young up to about 4 1 / 4 or 5 

 whorls. The shell is sculptured with quite regular growth- 

 strias, and a very fine but strongly expressed plication on the 

 median whorls. Besides this sculpture, at the fifth whorl 

 from the apex there begin to be coarse folds or ridges, stronger 

 on ventricose specimens, weaker on the turriculate. This 

 sculpture disappears near the aperture. 



13. P. LILJEVALLI d'Ailly. PI. 2, fig. 4. 



Shell imperforate, ovate-conic, thin but solid, lightly pli- 

 cate-striate. Under a scaly epidermis, which is lost from the 

 upper whorls and persistent near the aperture, it is shining, 

 fleshy-chocolate colored, the upper whorls blackish purple, 

 marked with fine, superficial bluish-white streaks, the median 

 whorls sometimes ornamented with wide brown streaks and 

 narrower white ones; the last 3 whorls encircled with a wide 

 whitish belt below the suture, last whorl encircled at the base 

 with a blackish-chocolate zone, extending up to the upper 



