434 Mr. H. B. Preston on 



The author has much pleasure in dedicating the present 

 genus to Mr. Diepenheim, through whose good offices, as 

 explained in the opening lines of this paper, all the species 

 described herein were obtained. 



Both the above new genera, judging by the shell-characters 

 alone, should be placed in the family Zonitidce. 



Diepenheimia iridescens, sp. n. 



Shell (as seen under a 1-inch objective) perforate, small, 

 suborbicular, depressedly conoid, yellowish brown, corneous, 

 polished, shining, highly iridescent ; whorls 4, regularly 

 increasing, the last gradually and slightly descending in 

 front, channelled and carinate just above the periphery ; 

 apical whorls smooth, the later whorls marked with radiate 

 growth-lines and sculptured with indistinct, rather closely 

 set, spiral strise ; suture narrowly, callously margined above, 

 deeply and rather widely channelled below, the sutural 

 channel being continued as the supra-peripheral channel on 

 the last whorl ; base of shell somewhat inflated, bearing the 

 same sculpture as on the spire; umbilicus narrow, deep; 

 columella margin descending in an angular curve ; labrum 

 acute, notched at the termination of the supra-peripheral 

 channel; aperture very obliquely subcrescentiic. 



Alt. l - 25, diam. maj. 2*75, diam. min. 2'5 (nearly) mm. 



Hab. Island of Beilan-Beilan, to the north of the Obi 

 Islands, Dutch East Indies {Mr. Diepenheim) . 



WlLHELMTNAlA, gen. nov. 



Shell corneous, turbinate, perforate, sculptured throughout 

 with very fine, spiral, punctate striee. 

 Bab. Moluccas. 

 Genotype. W. rnathildte, Preston. 



Wilhelminaia mathildce, sp. n. 



Shell (as seen under a 1-inch objective) minute, globosely 

 but rather depressedly turbinate, polished, shining, pale 

 brown ; whorls nearly 4 in number, regularly increasing, 

 sculptured with fine, punctate, spiral stria?, crossed by fine, 

 regular, transverse, hair-like growth-striae, which are more 

 closely set on the earlier whorls; suture rather lightly im- 

 pressed, margined above; base of shell somewhat convex; 

 umbilicus extremely narrow; columella margin very ob- 

 liquely descending, slightly curved, and outwardly dilated ; 

 labrum simple ; aperture oblique, subcrescentic. 



