16 THE NAUTILUS. 
The nearest neighbor is Planispira trochalia Benson, from the 
Andamans, from which, however, it is very distinct. This species 
would probably fall within the subgenus Trachia, even though its 
last whorl is not descending. The pitted surface indicates the pres- 
ence of hairs in young specimens—a special character of this group. 
13, Macrochlamys Dohertyin.s. Pl. 2, figs. 8, 9. 
Shell perforate, depressed, nearly planulate above, thin, shining ; 
excavated about the umbilical region. Whorls 43, convex, exca- 
vated at the sutures. Aperture lunate-circular. Lip simple, 
slightly reflected over the umbilical perforation. Growth lines 
strong below the suture, becoming faint on the periphery, a trace of 
faint revolving striz on the base. 
Alt. 6, maj. diam. 133, min. diam, 11 mm. 
Spire more depressed than in M. amboinensis Mart., var. perforata 
Bttg. (Java) and umbilicus smaller. Resembles also M. malaceana 
Pfr. (Sumatra), but has more impressed sutures. 
14. Helicarion albellus Mart. var. 
I refer this doubtfully to a/bellus, which has a somewhat shorter 
spire. Probably a localized variety of the Javan species. 
15. Glessula q 
Specimen too poor for satisfactory identification. 
16. Prosopeas argentean.s. PI. 2, fig. 10. 
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 exceedingly thin shining cal- 
lous. Growth lines closely crowded, strong and roughened. First 
or apical whorls regularly costulate. Color shining silvery white, 
becoming yellowish toward the base. Height 23, diam. 6 mm. 
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 acutissima Bttg. (O. hastatus 
Bttg.), of Java, in color and sculpture, but is less slender and has 
fewer whorls. It is a much larger shell than O. achatinacea Pfr., 
of Java. It differs from Opeas paroensis Bock, of Sumatra, in being 
a larger shell with a smaller apex. Stenogyra echelensis de Morg. 
of Perak, bears a strong resemblance to this Enganio form. 
