306 DRYM.EUS, SOUTH AMERICAN. 



Miss. Scient. Mex., Moll., i, p. 547. STREBEL, Beitr. Mex. Land- 

 und Siisswasser-Conch., v, p. 92, pi. 6, f. 1 (and probably la, b), 

 not " Form B," pi. 6, f. 2. MARTENS, Biol. Centr. Amer., Moll., p. 

 245. 



D. virgo Lea (gruneri Pfr.) is peculiar in the very long and 

 rather stout, slightly cylindric spire, the superficial sutures, and the 

 small aperture. The columella is decidedly pressed in at its inser- 

 tion, almost guttered; and the coloring varies from pure white to a 

 much interrupted, subobsolete pattern of brown dots arranged in 

 three spiral series. 



Lea's type specimen of B. virgo (pi. 45, fig. 41 from no. 105,076, 

 U. S. Nat. Mus.) agrees in all respects with immaculate specimens 

 of B. gruneri. The columella is straight and vertical, only weakly 

 twisted above. 



The Mexican habitat assigned B. gruneri by Pfeiffer is doubtless 

 an error. Whether the shells from Soganovo, Ecuador, figured 

 under this name by Strebel are the true gruneri or not I would not 

 attempt to decide without seeing them, but they certainly look like 

 it. The specimens before me were collected by Bland himself at 

 " Mendez, N. G." where both spotted and immaculate shells 

 occurred. 



D. DEMERARENSIS (Pfeiffer). 



Shell perforate, ovate-turrited, rather solid, striatulate, and under 

 the lens indistinctly somewhat decussated; opaque; whitish, irreg- 

 ularly marked with brown streaks. Spire lengthened conic, rather 

 acute. Whorls 6, little convex, the last more than one-third the 

 length of the shell, subangulate, the angle disappearing on the latter 

 part. Aperture oblique, truncate-oval ; peristome narrowly ex- 

 panded, the columellar margin arcuate, reflexed and overhanging 

 above. Alt. 20j, diam. 10; alt. of aperture 9J, width 51 mill. 



Demerara (Cuming coll.). 



Bulimus demerarensis PFR., P. Z. S., 1861, p. 24; Malak. Bl. 

 1861, p. 14 ; Moiiogr., vi, p. 51. 



D. DEMOTUS (Reeve). PL 43, fig. 81. 



Shell perforate, ovate-conic, rather thin, smooth, showing concen- 

 tric striae under the lens, shining; white, ornamented above with 

 rows of light red spots ; spire conic, slightly acute. Whorls 6, a 



