402 RINGICUI.A. 



K. soMERi Folin. PI. 46, figs. 52, 58. 



Shell small, ovate-globose, thick, solid, white, transversely mi- 

 nutely and regularly sulcate; whorls 6 to 7, subcarinate, the earlier 

 rapidly increasing, last very large, globose seven-tenths the shell's 

 length ; suture simple ; a])erture elongated, oblique, the margins 

 strongly thickened, toothed ; right margin very wide, the left in- 

 flated, broadly reflexed ; teeth large. Alt. 4, diam. 26 mill. {Folin). 



Strait of St. Vincent, Cape Verde Is. 



R. someri Folin, Les Fonds, i, pt. 1, pi. 14, pi. 1, f. 7. — Morl., 

 Journ. de Conch., 1878, p. 128, pi. 5, f. 12. 



R. MORiTzi Folin. PI. 46, fig. 32. 



Shell ovate-globose, somewhat glassy, generally much thickened 

 und snow-white, spirally and regularly sulcate, the sulci minute, 

 often vanishing ; whorls 4, rapidly increasing, the last very large: 

 globose, half the length of the shell ; suture simple ; aperture semi- 

 lunar; left margin thickened, terminating in a rounded canal; 

 right margin strongly reflexed above the base, inflated, toothed, 

 teeth 3 ; the margins joining above in a rather deep canal. Alt. 

 2-5, diam. 1-5 mill. {Folin.) 



Cagnabac, East coast of Africa. 



R. moritzi Folin, Les Fonds, i, pt. 2, p. 212, pi. 26, f. 10.— Morl., 

 Journ. de Conch., 1878, p. 129, pi. 5, f. 13. 



Smaller than R. someri with fewer whorls, wider and less rounded 

 basal canal, and thinner callus on the inner lip. 



R. sENEGALENSis Morlet. PI. 46, figs. 55, 56. 



Shell small, globulose, short, thick ; whorls 5, convex, separated 



by a deep suture ; the earlier whorls striulate, last whorl radially 



costellate, except on the back, two-thirds the entire length, rounded 



at base. Aperture coarctate, margins joined by a thick callus, the 



callus occupying the base; columella triplicate, the upper fold 



strong, dilated at base, forming a canal above, median fold short, 



lower fold delicate, contorted ; lip little arcuate, thick, provided 



with a long median callous subdentate at the ends. Alt. 3, diam. 



2-3 mill. {Morl). 



Coast of Senegal, in 72 meters (Schlumberger). 



R. senegalensis Morl., Journ. de Conch., 1882, p. 202, pi. 9, f. 2. 

 Distinguished by its very globose form, its striation, and espe- 

 cially the projecting callus of the lip. 



