AMPHIDROMUS, ODONTOSTOMUS. 169 



thicker lipped, parietal callus stronger ; suture more distinctly mar- 

 gined ; base less wide. 



Length 39.5, diam. 20.5 mill. Length 40.3, diam. 23.5 mill. 



Length 39.7, diam. 22 mill. Length 42.6, diam. 23.9 mill. 



Nha-trang, southern Annam (Fruhstorfer). 



The individual variations are even more numerous than in the 

 type, the following " forms" being distinguishable: A (flava), uni- 

 form yellow. B (alba), uniform white. G (tritaeniata), yellow 

 with 3 brown bands, the middle one sometimes lost. D (trizona), 

 white with 3 bands. .# (interrupta), like D, but the bands inter- 

 rupted and reduced to rows of spots. J^(confluens), like Z), but the 

 bands more or less widened and confluent. G (fusca), uniform 

 brown by widening and union of the bands, except for a white 

 sutural line. These forms occur both dextral and sinistral (Mlldff.}* 



Subsp. insularis Mlldff. Smaller, thinner-shelled, with the con- 

 tour of pachychilus. Island Bai-min, near Nha-trang. The forms 

 are less numerous than in the type or subsp. pachychilus, but this 

 may be due to the smaller number of specimens taken, which 

 includes pure white and banded white, banded yellow and nearly 

 uniform brown specimens, representing the form G. (Mlldff.}. 



A. INVERSUS subsp. ROSEOTINCTUS Mlldflf. (Vol. xiii,. pp. 169, 237). 

 Dr. von Mollendorff states that the characters of this race are 

 quite constant in more than 100 specimens examined from Fischaya. 

 It apparently deserves recognition as a separate race locally differ- 

 entiated from the annamiticus stock. (Nachbl. 1901, p. 50). 



A. H^EMATOSTOMA Mlldff. (Vol. xiii, p. 182). 



This unfigured species belongs to the group of A. mouhoti, its 

 nearest relatives being smithi Fult. and cruentatus Morel., according 

 to Mollendorff, Nachrbl. 1901, 50. 



A. XIENGENSIS Morlet. Vol. xiii, p. 194. 



Mr. H. Fischer (Journ. de Conchyl. xlix, 1901, p. 156, foot-note 

 no. 1) proposes to emend this name to correspond with the present 

 orthography of the original locality Xieng-Sen, making it A. xieng- 

 sensis. Such changes seem of doubtful utility. 



Genus ODONTOSTOMUS. 

 Dr. A. Doering has given an artificial key to the species of 



