156 DRYM^US. 



Var. perenensis Da Costa (pi. 48, tig. 54). Shell compressed- 

 umbilicate, ovate-pyramidal, covered with longitudinal close riblets ; 

 whitish, variegated with arrow-shaped bands. Whorls 6^, convex, 

 the penultimate more swollen than the others. Columella twisted, 

 receding. Aperture ample, inverted ear-shaped, lilac within ; per- 

 istome white, expanded and reflexed, a little squared at the base. 

 Length 46, diam. 23, length of apert. 22, width 17 mill. (Da Costa, 

 Proc. Malac. Soc. Lond. iv, 239, pi. 24, f. 5.) According to Mr. 

 Da Costa this form invariably has a less expanded lip than typical 

 expansus, the body-whorl is less ventricose, while the upper ones are 

 much more swollen ; the inaculation is also more pronounced and of 

 a darker color, while the umbilicus is much more contracted and not 

 so deep as in the type. The penultimate whorl is more swollen than 

 in var. aurisratti Phil., which resembles perenensis in color and 

 sculpture. 



D. SUBVENTRICOSUS Da Costa. PI. 48, fig. 48. 



Shell acuminate-oblong, umbilicate, rather thin, whitish, violaceous 

 brown. Whorls 7, subventricose, with impressed sutures, longi- 

 tudinally rudely elevate-striate. Aperture ovate, purplish inside, 

 exceeding two-fifths the total length ; peristome acute, a little re- 

 flexed, white-margined ; columella slightly reflexed. Length 30, 

 diam. 14; aperture, length 13, width 8 mill. (Da Costa.) 



Colombia : Bogota. 



D. subventricosus Da C., 1. c., p. 239, pi. 24, f. 4 (Oct. 1901). 



D. EXOTICUS Da Costa. PI. 48, fig. 52. 



Shell ovate-conic, scarcely umbilicate, rather thin, smooth, glossy, 

 whitish, longitudinally streaked and maculate with violaceous-brown. 

 Whorls 6, somewhat swollen, the sutures impressed. Aperture 

 ample, about one-half the total length, streaked with violaceous 

 within ; peristome acute and reflexed, columella dilated, reflexed. 

 Length 23.5, diam. 11; length of aperture 11, width 7.5 mill. 

 (Da Costa.) 



Colombia : The hot country, upper Magdalena River. 



D. exoticus Da C., 1. c., p. 239, pi. 24, f. 10 (Oct. 1901). 



D. ELSTERI Da Costa. PL 48 fig. 53. 



Shell oblong-turreted, imperforate, a little solid, rather smooth, 

 very minutely striated under the lens ; whitish, with reddish streaks 



