532 Mr. II. B. Preston on new 



thickened, almost vertically descending, bulging inwardly in 

 the median part; labrum simple, receding below; aperture 

 subovate. 



Alt. 1*75, diam. maj. 3 mm. 



Hub. Mount Pitt, Norfolk Island (R. Bell). 



Nitor retinaculum j sp. n. 



Shell small, depressedly conic, thin, transparent, somewhat 

 shining, yellowish brown ; whorls 4, regularly increasing, 

 the last subangled at the periphery, sculptured only with 

 rather closely set, oblique, arcuate plicse, which are more 

 noticeable on the later convolutions; suture impressed; 

 columella margin curved above, very obliquely descending 

 and thickened inwardly into a whitish loop-like lamella, 

 visible through the test; labrum acute; aperture obliquely 

 and compressedly sublimate. 



Alt. 1'5 (nearly), diam. maj. 3, diam. min. 2'5 mm. 



Bab. Ball's Bay, Norfolk Island {It. Bell). 



Macgillivrayella, gen. nov. {Zo nit idee). 



Shell depressedly turbinate, small, vitreous, somewhat 

 broadly perforate. 



Genotype : M. crystallina, Preston. 



Macgillivrayella crystallina, sp. n. 



Shell small, depressed, orbicular, white, semitransparent ; 

 whorls 3^, sculptured with rather fine, somewhat closely set, 

 oblique, arcuate strise, which become obsolete on the base of 

 the shell ; suture deeply impressed; umbilicus wide, mode- 

 rately deep; columella margin descending in a curve; 

 labrum acute, receding below ; aperture roundly sublunate. 



Alt. 1, diam. maj. 2'5, diam. min. 2'25 mm. 



Hah. Norfolk Island. 



Joiiannesoconcha, gen. nov. {Zonitidie). 



Shell minute, vitreous, turbinate, multispiral, umbilicate. 

 Genotype : J. multivolva, Preston. 



Johannesoconcha multivolva, sp. n. 



Shell minute, turbinate, thin, white, polished, shining ; 

 whorls 5, rather rapidly increasing, the last scarcely ascending 

 in front, faintly marked with lines of growth ; base of shell 



