80 HOLOSPIRA. 



the outer wall below its middle; and a basal lamella about a 

 half whorl in length ; this and the palatal fold standing on the 

 ventral side in the individual opened. 



Length 17.4, diam. 4.7, longest axis of aperture 3.7 mm. 



Length 17, diam. 4.5, longest axis of aperture 3.8 mm. 



Length 16, diam. 4.7, longest axis of aperture 3.7 mm. 

 Mexico: Sierra Guadalwpe, 6500 ft. elevation (E. W. Nelson). 



This species resembles H . teres Mke. in contour, and when 

 the interior of that species is investigated it may prove to be a 

 variety thereof. However, with a somewhat smaller size, H. 

 nelsoni has more whorls, and the coloration differs. In H. 

 goniostoma the internal column is wider above, and the sculp- 

 ture apparently finer and more distinct. It does not seem 

 closely related to any other described species. Occurred with 

 H. dalli and H. strebeli. 



6. H. PFEIFPERI (Menke) . PL 22, figs. 49, 50, 51. 



Shell ovate-oblong, subfusiform, swollen from the middle 

 downwards; apex conic, entire, a little obtuse; rimate, thin, 

 pellucid, pale yellowish, densely and very finely lamellose- 

 ribbed. Whorls 12, a little convex, the last not drawn out, 

 adnate posteriorly. Aperture rounded, the peristome con- 

 tinuous and reflexed. Length 7.6, diam. 2.5 lines [about 15.4, 

 5 mm.] (Mke.}. 



Mexico: Tehuacan, in the State of Puebla (Liebmann). 



Cylindrella pfeifferi MENKE, Zeitschr. f . Malak., 1847, p. 1 ; 

 PHILIPPIC Abbild. u. Beschreib., iii, p. 6, pi. 3, f. 4. PFR., 

 Monogr., ii. p. 382; Conchyl. Cab., p. 60, pi. 6, f. 30, 31. 

 Holospira pfeifferi Mke., TRYON, Amer. Journ. of Conch., iii, 

 p. 313, pi. 15, f . 34 (but not the locality) ; Monogr. Terr. Moll. 

 U. S., p. 140, pi. 15, f. 34. FISCH. & CROSSE, Miss. Scient. 

 Mex., Moll., i, p. 323 (exclusive of var. 6). STREBEL, Beitrag, 

 iv, p. 84, pi. 13, f. 12. v. MART., Biologia, p. 280, exclusive of 

 varieties. CROSSE, Journ. de Conchyl., xl, 1892, p. 260 (ex- 

 clusive of var., p. 261, pi. 5, f. 7, 7 a). 



Pfeiffer, whose material was evidently part of the original 

 lot from Liebmann, gives the dimensions as length 17%, diam. 

 in the middle 5% mm., the aperture 4 mm. long, 4% wide, 

 whorls 12. 



