24 PROSOPEAS. 



16. P. HOLOSERICUM Boettger, n. sp. PI. 3, figs. 93, 94. 

 Shell subrimate, slender, turrited, thin, pale greenish-cor- 

 neous, very densely and finely striate, the stria? oblique, 

 arched forward below the suture, the first 2y 2 whorls verti- 

 cally costellate, usually worn. Whorls 8 l /2, convex, the last 

 two much less so, somewhat flattened. Suture narrow but 

 deeply incised, oblique. Aperture narrow, oblique. Colu- 

 mella straight, with reflexed, not wholly adnate edge. Length 

 19.5, diam. 4.8, length of aperture 6 mm. 



Java. Sumatra at Sukuranda (G. Schneider). 



P. holosericum BTTG. in coll. Acad. Nat. Sci., no. 69973. 

 MARTENS, Nachrbl. D. Mai. Ges., 1900, p. 9 (no description). 



This is apparently described here for the first time; or at 

 all events, I have been unable to find a description of the 

 species. It is a smaller shell than the closely related P. acu- 

 tissimum, with the mouth narrower below, and the columellar 

 reflection not wholly appressed, leaving a long but very nar- 

 row umbilical fissure. 



17. P. ARGENTEUM Henderson. PI. 6, fig. 71. 



Whorls fully 8, slightly convex. Apex obtuse. Sutures 

 well impressed. Aperture oblique, elongate, pointed above, 

 dilated in the middle, narrow below. Lip sharp and thin; 

 columella slightly arcuate; ends of lip connected by an ex- 

 ceedingly thin shining callous. Growth-lines closely crowded, 

 strong and roughened. First or apical whorl regularly costu- 

 late. Color shining silvery-white, becoming yellowish toward 

 the base. Length 23, diam. 6 mm. (Henderson). 



Enganio Island, southwest of Sumatra (Wm. Doherty). 



Prosopeas argentca HENDERSON, Nautilus, xii, p. 16, pi. 2, 

 f. 10 (June, 1898). 



'The Stenogyras are widely distributed throughout the 

 Malayan province, being represented in all the islands by 

 more or less closely allied species. This resembles Opeas acu- 

 tissima Bttg. (0. hastatus Bttg.), of Java, in color and sculp- 

 ture, but is less slender and has fewer whorls. It is a much 

 larger shell than 0. achatinacea Pfr., of Java. It differs 

 from Opcas paioensis Bock, of Sumatra, in being a larger 



