Oliver. — Mollusca of the Kermadec Islands. 521 



groove separating the inner lip from the body-whorl. Sculpture : Proto- 

 conch smooth, shining. Shell smooth, faintly microscopically marked 

 spirally, also transversely, with growth-lines. Colour white. 



Height, 2-8 mm. Diameter, 1 mm. 



Habitat. — Dead shells dredged on gravelly bottom in 10 m. to 30 m. near 

 Sunday Island. 



Epigrus gracilis n. sp. Fig. 14. 



Description of Type Specimen. — Shell elongate, slender, the whorls in- 

 creasing but little in size. Whorls 4|, flattened, loosely coiled, margined 

 above, suture deeply impressed. Aperture oval, peristone continuous, thin, 

 inner lip separated from body-whorl by a distinct groove. Sculpture : 

 Protoconch smooth. Shell with spiral threads and lines. On 1st adult 

 whorl about 5 narrow low threads, which broaden and increase on succeed- 

 ing whorls, there being on the body-whorl about 6 principal and as many 

 smaller spiral threads, the interstices having under a high power a rough 

 pitted appearance. Colour white. 



Height, 1-7 mm. Diameter, 05 mm. 



Habitat. — Dead shells dredged on gravelly bottom in 10 m. to 30 m. off 

 Sunday Island. 



Cerostraca n. gen. 



Shell ovate, thin, whorls rounded, suture impressed. Aperture detached, 

 circular, body- whorl anteriorly having a callosity just above the produced 

 and expanded outer lip. 



Type. — C. iredalei Oliver. 



Cerostraca iredalei n. sp. Fig. 15. 



Description of Type Specimen. — Shell ovate, apex blunt, the body-whorl 

 bearing in front a prominent transverse callosity. Aperture completely 

 detached from body-whorl, circular, the margin thin and expanded. Sculp- 

 ture : Shell quite smooth. Colour : Protoconch white. Adult whorls 

 glassy pink, a dark -pink spiral line below the suture, and another on the 

 base of the whorl-shell. Anterior callosity dark pink. Peristome white. 



Height, 1-3 mm. Diameter, 0-7 mm. 



Habitat. — Dead shells dredged on gravelly bottom in 10 m. to 30 m. off 

 Sunday Island. 



Amphi thalamus sundayensis n. sp. Fig. 16. 



Description of Type Specimen. — Shell minute, ovate, apex blunt. Whorls 

 4, flattened, suture impressed. Aperture detached, broadly elliptical, 

 slightly angled behind. Peristome thickened, a ridge connecting its pos- 

 terior end with the body-whorl. Umbilical furrow wide. Sculpture : The 

 whole shell quite smooth. Colour : Light olive-brown, the suture, peri- 

 stome, and lower part of body-whorl darker. 



Height, 1-2 mm. Diameter, 0-6 mm. 



Habitat. — Dead shells dredged on gravelly bottom in 10 :n. to 30 m. near 

 Sunday Island. 



Heterorissoa secunda Iredale. 



Heterorissoa secunda Iredale, Pro. Mai. Soc, x, 222, 1912. 



Recorded, Iredale, I.e. 

 Habitat. — Dead shells common in dredgings in 10 m. to 30 m. off Sunday 

 Island. 



