DRYM^US, SOUTH AMERICAN. 263 



sharp, not expanded, regularly arcuate; columella weakly folded, 

 the edge reflexed and appressed. 



Alt. 29*, diara. 15? ; alt. of aperture, 17 mill. 



Alt. 31 -3-, diara. 15* ; alt. of aperture, 15 mill. 



Ecuador : Pomasqui Valley (Bourcier) ; Quito (Martinez and 

 others) ; Machache (Paz) ; Tumbaeenti (Boetzkes) ; Tumbaco, Chil- 

 logallo (Cousin). 



Bulimus nystianus PFR., P. Z. S., 1852, p. 154; Conchylien Cab- 

 inet, p. 99, pi. 32, f. 15, 16 ; Monogr. iii, p. 374; iv, 444; vi, 80; 

 viii, 112. HIDALGO, Journ. de Conchyl., 1870, p. 50 ; Mol. Viaje 

 al Pacifico, p. 78. Goniostomus nystianus MILLER, Mai. Bl., xxv, 

 1878, p. 192. Thawnastus (?) nystianus COUSIN, Bull. Soc. Zool. 

 France, 1887, p. 220. 



The wide range of color variation is alluded to below. In the 

 prominence of the basal angle there is great mutation, it being quite 

 strong in some, nearly obsolete in other specimens. 



Hidalgo mentions these color-forms: (1) shell unicolored, pale 

 citron, the columella roseate ; (2) with distant, distinct streaks, the 

 basal angle whitish, and (3) with transverse bands of the same color 

 as, and crossing, the streaks, the basal angle white. 



Cousin writes that all around Quito, at about 2,840 meters alt., it 

 is of large size ; at Tumbaco, at 2,390 meters, intermediate, and at 

 Chillogallo, 2,893 meters above sea level, a small variety ; at all of 

 these localities the variety lutea occurs. "TA. nystianus varies ac- 

 cording to locality, in size and coloration. All the intermediate 

 colors between yellow and greenish-black occur" (Cousin}. 



" Var. nigricans. I collected along the railroad between Pomasqui 

 and Chilguiltina, canton of Quito, several individuals of this 

 species, all of great size and a greenish-black color" (Cousin). 



D. CANALICULATUS (Pfeiffer). PI. 40. fig. 8. 



Shell umbilicated, obliquely fusiform, wrinkle-striate, shining; 

 whitish, marbled with flesh-color and reddish. Spire turrited-conic, 

 acute. Whorls 7, slightly convex, the last a trifle longer than the 

 spire, strongly pinched into a keel at base. Columella arcuate, pro- 

 longed forward. Aperture oval, channelled at base ; peristome sim- 

 ple, thin, the right margin a trifle expanded, columellar margin 

 dilated, reflexed. Alt. 37, diam. 14; aperture 19 mill long (Pfr.). 



Bolivia. 



