220 AMPHIDROMUS, GROUP XVIII. 





istome. This does not occur in porcellanus or sumatranus, so far as 

 16 of the former, 3 of the latter show. There are three pattern- 

 varieties : 



(a) Two brown bands on the under side, two rows of paler spots 

 on the visible portion of the earlier whorls, (b) Bands of the under 

 side vanished, excepting the narrow one about the columella; the 

 two spot-rows of the upper whorls equally distinct in one specimen, 

 in the other disappearing on the penultimate whorl, very pale on the 

 two preceding, (c) Uniform yellow except for the band around the 

 columella and behind the lip. (Martens.) 



Sumatra: Deli (L. Marten, form a); Sukaranda, Upper Lankat 

 (Schneider, forms b and c). 



Amphidromus semifrenatus MARTENS, Nachrbl. d. d. Malak. Ges., 

 xxxii, p. 8 (Feb., 1900). 



A. HOSEI Smith. PI. 63, fig. 89. 



Shell small, rimate, sinistral, elongate, conic ; a narrow reddish- 

 purple line encircling the middle of the last whorl, and above the 

 suture, and toward the apex spotted with brown, under a very thin 

 pale yellow cuticle. Whorls 7, a little convex, striated with very 

 delicate, oblique growth-lines, slowly and regularly increasing, the 

 last one short, stained with black around the narrow umbilical chink. 

 Aperture inverted auriform, pale yellowish with a median reddish- 

 purple line, a little exceeding one-third the total length of the shell ; 

 peristome white, narrowly expanded and reflexed, the columellar 

 margin thickened and narrowly dilated. Length 31, diam. 14, aper- 

 ture 11 mill. long. (Smith). 



Borneo : Men, Sarawak (C. Hose). 



Amphidromus hosei E. A. SMITH, P. Z. S., June, 1895, p. 115, 

 pi. 3, f. 20 FULTON, t. c., p. 81. 



"A small species, rather like A. suspectus Martens, from Timor 

 and Sumbawa. It is differently colored, the increase of the whorls 

 is slower, and the body-whorl and aperture are smaller. The apex 

 is not black, and the fourth and fifth volutions exhibit some pale 

 brown spots or stripes. Only a single specimen examined " (Smith). 



" Near flavus in form, with a thin yellowish green epidermis as in 

 sylheticus, but easily distinguished from both by the single color-band 

 encircling the last whorl " {Fulton). 



