AMERICAN OPEAS. 197 



pi. 16, f. 4 (Feb. 3, 1870). Opeas t., MARTENS, Biol. Centr. 

 Amer. Moll., p. 296, with var. subovale, pi. 17, f. 12. 



The type or a cotype of this species received from Tate is 

 bleached and minutely perforate. It tapers regularly to the 

 very obtuse apex. The surface is sculptured with very regu- 

 lar and delicate riblets, straight on the spire, but somewhat 

 arcuate on the last whorl. These riblets are a trifle closer and 

 weaker 'than in the Yucatan 0. micro,. In other respects I 

 am quite unable to see any difference from micro, of the same 

 size. The shell measures, length 4.9, diam. 2, aperture 2 mm. ; 

 whorls 5%. This is the specimen badly figured in Amer. 

 Journ. Conch., and corresponds in size with Tate's measure- 

 ment, but it has not the number of whorls called for in his 

 description, which I think may have been partly taken from 

 0. goodalli, of which there were specimens in the same vial. 

 Tate's identifications of Stenogyrina? were chiefly erroneous; 

 and this applies also to a good many other snails, listed in 

 his paper, as I know from the set sent to Mr. Tryon. 



Var. siibovale Martens (PL 28, fig. 65), "a little more ovate, 

 umbilicus narrow but not closed. Shell ovate-subturrited, 

 vertically lightly striatulate, whorls 6, -a little convex, the 

 last, measured at the back, contained 2% times in the alt. ; nar- 

 rowly perforate, the aperture rhombic-elliptical, columellar 

 margin slightly thickened. Length 5.5, diam. 2 aperture 

 2 x 1.33 mm. S.-W. Costa Rica at Turubanes, 500 meters 

 elevation. ' ' 



Var. cuencanum (Pfeiffer). 



Shell subperf orate, oblong- turrite ; rather solid, chordate- 

 costulate, pellucid, greenish-white. Spire regularly turrite, 

 the apex rather obtuse. Whorls 6, a little convex, the last 

 about one-third the total length, slightly compressed basally. 

 Columella vertical. Aperture vertical, truncate-oval, peris- 

 tome simple, unexpanded, the columellar margin shortly re- 

 flexed, somewhat free. Length 8, diam. 3.25 mm. ; aperture 

 2.66x1.5 mm. (Pfr.). 



Ecuador: Province of Cuenca (Fraser; Cuming coll.). 



Bulimus cuencanus PFR., Malak. Blatter v, 1858, p. 239; 



