RHODEA. 235 



the basal and outer angles. Internal axis ascending in an 

 open spiral, at the aperture forming a strong columellar fold 

 above, and continuing to the base; columella concave below 

 the fold, calloused, and sometimes truncate at the base. 

 Viviparous. Soft anatomy unknown. Type E. calif ornica. 



Distribution, Andean region of Colombia and Ecuador. 



A very distinct genus, readily known by its pillar-like 

 form, 'acute peripheral keel and gyrate axis. Reproduction 

 is viviparous, as first noticed by Bland; the young shells 

 at birth having an oblong imperforate shell of about 2 1/2 

 whorls, with the columella vertical, somewhat calloused, and 

 obliquely truncate basally (pi. 38, fig. 4). The earlier 

 whorls are convex, but the sixth already shows an angle at 

 the basal periphery. At this stage the columella is sub- 

 vertical and very weakly, obliquely excised below (pi. 38, 

 fig. 5). Specimens of 8 whorls have a well developed keel, 

 concave base, and a spiral swelling around the columella, 

 which is becoming weakly gyrate (pi. 38, fig. 6). The fore- 

 going account is based upon a series of young E. calif ornica. 



The individual therefore passes through stages like Lep- 

 ii tt aria and Obeliscus before assuming the special features of 

 Elwdea. I consider the genus to stand nearer Obelise us than 

 to any other known group. This was also the opinion of 

 Dohrn. 



1. R. CALIFORNIA (Pfeiffer). PI. 38, figs. 1 to 6, 10. 



Shell subulate, thin, obliquely very closely rugose-striate, 

 waxy- whitish ; whorls 12 to 13, the upper ones convex, last 

 3 or 4 flat, the last whorl a little more than one-sixth the total 

 length, acutely carinate at the base, somewhat excavated be- 

 low the carina; columella arcuate, reaching the base, thick- 

 ened, subtruncate. Aperture sub tetragonal, peristome sim- 

 ple, acute. Length 23, diam. 3.5, aperture 4 x 2.25 mm. 



(Pfr.). 



Colombia: Bogota (Akhurst) ; Marmato (Bland). 



Acliatina californica PFR., Symbolae ad Hist.. Hel. iii, p. 

 89 (1846) ; Monogr. ii, p. 266; vi, 236. REEVE, Conch. Icon, 

 v, pi. 20, f. 115. BINNEY, Terr. Moll. U. S. iv, p. 26, pi. 79, 



