244 PEEIDERIOPSIS. 



confluent at the suture, some of them reaching to the suture 

 below; lower part of the last whorl chestnut-black, banded 

 with buff flames. Suture rather deep, narrowly plicate- 

 margined on the last whorl. Apex somewhat obtuse. Whorls 

 7, regularly increasing, convex, ornamented with many deli- 

 cate, oblique and regular growth-lines; the second and third 

 densely spirally striate, the following sculptured with trans- 

 verse striae, which are inconspicuous below, evanescent on 

 the penult, and last whorls. Last whorl lightly inflated, 

 subangular. Columella nearly vertical, slightly thickened 

 above, violaceous, reflexed over the narrow perforation, the 

 margin brownish, joined to the lip by a very thin callous. 

 Lip acute, arcuate, slightly depressed in the middle, forming 

 an acute angle with the whorl above, and a subobtuse angle 

 with the columella. Aperture quadrate-ovate ; within slightly 

 thickened, blue-white and opalescent, the external markings 

 visible. Length 41.5, diam. 17.5, length apert. 16, width 10 

 mm. (D. et P.). 



Congo Free State : Island of Mvula, facing the Lowa river 

 (P. Dupuis). 



Perideriopsis formosa D. et P., Ann. Soc. Roy. Malac. 

 Belg., xxxvi, Bulletins des seances, 1901, p. xxxiv, figs. 1, 2 

 (March, 1902) ; with var. pallida, p. xxxv. 



2a. Var. pallida Dupuis et Putzeys. 



Ground-color uniform roseate-brown; the white and yel- 

 low flames are as in the type, but there are no dark bands 

 at suture and periphery. Size and locality of the type. 



3. P. FALLSENSIS Dupuis et Putzeys. PL 17, figs. 82, 83. 



Shell solid, conic-turrite, very narrowly perforate, whit- 

 ish, a little shining, striate; apex obtuse; painted with flam- 

 mules dilated above the suture, or with rather narrow streaks, 

 of reddish chestnut, sometimes interrupted. Whorls 7-8, 

 convex, joined by a slightly margined and crenulate suture, 

 the upper granulose, the last flattened in the middle, sub- 

 angular at the periphery. Aperture ovate-sub rhomboidal, the 

 lip acute, a little reflexed, slightly thickened within; colu- 



