OPEAS JAVANICUM. 139 



deeply impressed suture, the apex obtuse, smooth. Aperture 

 narrow, the outer lip thin, arched forward near the upper 

 insertion, retracted to the suture. Columella vertical, nearly 

 straight, calloused and obliquely truncate basally, the colu- 

 mellar margin reflexed and appressed. Length 9, diam. 3.1, 

 aperture 3.1 mm. 



The oblique but distinct columellar truncation and the 

 fine spiral striation (not readily visible with an ordinary 

 hand lens) are prominent features of this species. Half- 

 grown specimens have the columella as strongly truncate as 

 the larger ones. Probably none of the lot have reached 

 maximum size. 



0. javanicum occurs also in Mauritius (pi. 23, fig. 18), at- 

 taining a larger size than elsewhere, well-grown shells being 

 13 mm. long, while the largest measure, length 15, diam. 4.1, 

 aperture 4 mm., whorls 9%, or a little shorter with the same 

 diameter. The sculpture of sharp, densely crowded striae is 

 the same in shells from Mauritius, Java, Sumatra and 

 Hawaii. When unworn, the striae bear narrow brownish 

 cuticular laminae. 



It remains to be determined just what relation 0. javani- 

 cum bears to achatinaceum Pfr. which I have placed in 

 Prosopeas (p. 21) , since I have not myself seen achatinaceum. 

 If javanicum were larger it would probably be considered to 

 be a Prosopeas. It has the sculpture of that group, and had 

 I studied it fully before the monograph of Prosopeas was 

 published, I would have included javanicum therein. 



This species seems to have been mistaken for 0. clavulinum 

 by some authors. Mr. Sykes agrees with me in considering 

 the following Hawaiian form a synonym. 



0. henskawi Sykes. (PI. 12, figs. 14, 16.) " Shell subper- 

 forate, turreted, somewhat solid, with closely-set, well- 

 marked, curved, longitudinal striae; light-yellowish horn- 

 color. Spire well drawn out, suture well marked, but the 

 whorls not so shouldered as in 0. junceus. Whorls 8%, 

 plano-convex, the last whorl inflated, and measuring about 

 half the total length of the shell, somewhat compressed at the 



