240 OBELISCUS. 



forming an obtuse apex, to the fifth or sixth tumid and 

 greenish, following three flat, the last whorl carinate, some- 

 what excavated beneath ; suture impressed, irregularly crenu- 

 late. Aperture subtetragonal, somewhat channelled anter- 

 iorly. Columella thickened, arcuate, screw-shaped inside. 

 Peristome simple, acute. Length 15, diam. 3 mm. (Jouss.). 



Ecuador: Los Puentos (Cousin). 



RJwdea equatorensis Jouss., Bull. Soc. Philom. Paris ii, 

 p. 37, pi. 1, f. 17 (1900). 



This shell resembles R. californica, but it is smaller and 

 of less regular growth, whorls v, vi and vii being larger than 

 the succeeding and greenish while the rest are dull. The 

 keel of the last whorl projects less and the base is less 

 excavated. 



Genus OBELISCUS Beck, 1837. 



Obeliscus BECK, Index Moll., p. 61, for (1) calcareus, (2) 

 sceptrum, (3) obtusatus, (4) decollatus, (5) obeliscus, (6) 

 .gnomon, (7) sylvaticus, (8) subuliformis, (9) septenarius, 

 (10) stylus, (11) bacterionides, (12) micro,, (13) annaensis, 

 (14) gracillimus, (15) clavulus, (16) goodalli, (17) oryza, 

 (18) mimosarum, (19) brepkos. Not Obeliscus Humphrey, 

 Museum Calonnianum, p. 24 (1797). Cf. Herrmannsen, In- 

 dicis, ii, p. 131. 



Stenogyra SHUTTL. (in part), Beitrage zur naheren Kennt- 

 niss der Land- und Susswasser-Mollusken der Insel Portorico, 

 in Mittheilungen der naturforschenden Gesellschaft in Bern, 

 aus den Jahre 1854, p. 45 (March, 1854) ; and in Annals of 

 the Lye. of Nat, Hist., N. Y., vi, p. 70, foot-note (March, 

 1854) ; and of many subsequent authors. Bulimus of the 

 older writers. 



Shell imperforate or nearly so, subcylindric or taperinir, 

 usually rather large, solid and opaque; whorls 9 to 18, some- 

 what convex, not carinate. Embryonic whorls smooth, the 

 summit obtuse. Aperture ovate, the outer lip simple and 

 short, columella concave or vertical, continuous or indis- 

 tinctly truncate at base. Viviparous, the embryonic shell 

 globose or oblong, of about 3 whorls, and very small com- 

 pared with the adult. Type 0. obeliscus. 



