CERAS. 155 



crowded, irregular costulation with, the exception of the first 

 four whorls, which are smooth except for a short and elegant 

 sutural denticulation. 



Genus CERAS Dupuis et Putzeys, 1901. 



Ceras D. et P., Bulletins des Seances, Societe Royale 

 Malacologique de Belgique, 1901, Seance du 6 juillet, p. 

 xxxviii. 



"Shell thin, covered with a very thin cuticle. Embryonic 

 first whorl at first obliquely ascending, then horizontally in- 

 voluted over the left part of the spire, forming an excentric 

 concave apex. Following whorls numerous, slowly increasing, 

 flattened, forming a long, subulate spire. Last whorl trun- 

 cate-carinate, the keel projecting, bimarginate. Columella 

 regularly very concave, abruptly truncate in front. Aper- 

 ture subquadrate, the lip simple." (D. et P.). 



The two species known are viviparous, those examined 

 containing fifteen or twenty embryonic shells. This char- 

 acter, the uniform gray color of the animal and its small 

 foot, are similar to Subulona martensi, and both differ from 

 the true Subulinas of the same region, which are oviparous, 

 with the animal outwardly yellow or yellowish and the foot 

 is more lengthened. (D. et P.) 



Type C. dautzeribergi. Distribution, Congo basin. 



This group is known to me only by the above description. 



1. C. DAUTZENBERGI Dupuis et Putzeys. PL 44, fig. 3. 



Shell very glossy, translucent, covered with a chestnut 

 epidermis, irregularly marked transversely with dark lines. 

 Whorls 12, sculptured with delicate oblique, usually wavy 

 growth-lines and occasional folds, and numerous inconspicuous 

 spiral striae. Length 30, diam. 6, length of aperture 4.5, 

 width 3 mm. (D. et P.). 



Congo: Nsendwe (P. Dupuis). 



C. dautzeribergi D. et P., t. c., p. xxxviii, f. 10. 



2. C. MANYEMAENSE Dupuis et Putzeys. PI. 44, figs. 4, 5. 

 Shell a little glossy, translucent, pale buff-gray. Whorls 



