158 OPEAS, CEYLON. 



striation, which becoming stronger on the post-embryonic 

 whorls produces a fine, irregularly developed crenulation of 

 the suture, the latter becoming smooth again lower down. 

 Later whorls somewhat flattened. Suture well impressed. 

 Aperture vertical, much shorter than in 0. gracile; outer lip 

 weakly arcuate, a little arched forward; basal margin well 

 arched; columella rather straightened, the edge reflexed. 



Length 11, diam. 3.4, aperture 2.9 mm. ; whorls 8%. 



Length 12.9, diam. 3.5, aperture 3.1 mm. ; whorls 10. 



Ceylon. Types no. 58330 A. N. S. P. 



This form is readily selected from among 0. gracile by 

 its short whorls and small, wider mouth, with a deep bay 

 where the columella joins the parietal wall. I do not see, in 

 the great number of 0. gracile before me, any approach to 

 this form. Named for Mr. E. R. Sykes of London. 



36. 0. LAYARDI (Benson) . PI. 4, figs. 19, 20 ; pi. 16, figs. 82, 83. 



Shell imperforate, elongate-turrited, thin, arcuately striat- 

 ulate, whitish, covered with a thin, corneous epidermis. Spire 

 elongated, the apex obtuse, suture somewhat deep, occasion- 

 ally eroded-denticulate. Whorls T 1 /^, convex, the last im- 

 pressed behind the columella. Aperture oblique, long-ovate, 

 narrow above; peristome thin, acute; lip arcuate, the colu- 

 mellar margin thickened, moderately twisted. Length 12.5, 

 diam. 4 mm.; length of aperture 4, diam. scarcely 2 mm. 

 (Bens.). 



Ceylon: Moopana, Bootelle, etc. (Layard). 



Spiraxis layardi BENS., Ann. Mag. Nat. Hist. (3 ser.), ix, 

 p. 90, 1863. PFR., Monogr., vi, p. 190. HANLEY & THEOB., 

 Conch. Indica, pi. 79, f. 2, 3. 



This is a form of somewhat uncertain relationships. The 

 subtruncate, 'calloused columella recalls Tortaxis, yet the deli- 

 cacy of the shell, its small apex, and the oviparous repro- 

 duction, are characters of Opeas. It is probably related to 

 0. avenacea Morel., javanicum Bve., etc., which have the 

 columella similarly truncate. 



Shell is pale yellowish-corneous, more or less transparent, 

 very glossy, with weak sculpture of arcuate growth-wrinkles. 



