RHODEA. 237 



without much gloss. "Wliorls 11 to 12, the upper a little 

 convex, the middle ones flat, the last two concave in the 

 middle, separated by an acute projecting carina; the base of 

 the last whorl is excavated around the thread-like, nearly 

 straight, much protracted and basally truncate columella; 

 margin of the peristome arcuate ; columella encircled with a 

 wide lamina. Length 34 to 36, diameter in the middle 5 to 

 6 mm.' (Dohrn) . 



Colombia: upper part of the Magdalena valley (Wallis). 



Elwdea ivaUiaiana DOHRN, Nachrbl. d. D. Malak. Ges., vii, 

 1875, p. 57, Jahrb. d. D. Malak. Ges. ii, 1875, p. 307, pi. 10, 

 f. 7, 8. CROSSE, Journ. de Conchy!, xxiv, 1876, p. 21, pi. 1, 

 f. 3. 



4. R. CROSSEANA Da Costa. PI. 38, fig. 9. 



Shell cylindrdc, slowly narrowing towards the apex, sub- 

 pellucid, corneous. Whorls 13, the upper 3 or 4 smooth, con- 

 vex, the following 2 or 3 convex, the rest nearly flat, ob- 

 liquely delicately and closely striate, separated by an oblique 

 suture which is carinate in the last few whorls; last whorl 

 acutely carinate, deeply excavated below the carina. Aper- 

 ture irregularly quadrate, bicanaliculate ; columella spirally 

 twisted, ascending within, forming an umbilicus penetrating 

 nearly to the apex; lip thin, angular in the middle, chan- 

 nelled, concave below. Length 31, diam. 5 mm. (Da Costa). 



Rliodea crosseana DA C., Proc. Malac. Soc. Lond. iii, p. 

 305, fig. v (Oct. 1899). 



Colombia: Dagua river (W. F. H. Rosenberg). Type in 

 Brit. Mus. 



Very much larger than R. pfeifferi Crosse, with differently 

 proportioned whorls; the body- whorl more deeply excavated 

 beneath, and the columella differently convoluted and more 

 deeply reflexed, so that the basal channel is conspicuously 

 deeper (Da C.). 



5. R. GIGANTEA Mousson. PI. 38, figs. 17, 18, 19. 



Shell imperforate, turrite-cylindric, rod-Shaped, obliquely 

 closely and evenly plicate-striate, lusterless, covered with a 



