Murdoch. — Additions to Marine Mollusca of N.Z. 229 



pearance. Apex minute ; the last whorl longer than the. spire. 

 Without sculpture except the microscopic growth-lines. Sutures 

 impressed and lightly margined. Aperture ovato-subcircular, 

 peristome continuous ; the columella and lip broadly expanded, 

 the latter shortly descending. Length, l - 94 mm. ; breadth, 

 66 mm. 



Type in the Colonial Museum. 



Hab. Whangaroa Harbour (Mr. A. Hamilton). 



Of this minute form there are only two examples. It is 

 perhaps nearest to R. lubrica* Suter, from Stewart Island. 



Rissoa microstriata, n. sp. Fig. 25. 



Shell minute, ovate-elongate, smooth and white. Whorls 5, 

 somewhat swollen at the shoulders, thence gently flattened to 

 the sutures ; the latter impressed and lightly margined. Apex 

 minute ; last whorl longer than the spire. The sculpture con- 

 sists of microscopic dense spiral stria?, broken up into variable 

 lengths by the irregular lines of growth. Aperture obliquely 

 broadly ovate ; lip slightly thickened, a callus spreading across 

 the body to the columella ; the latter thickened and lightly 

 reflected. Length, 2" 11 mm. ; breadth, 1'08 mm. 



Type in the Colonial Museum. 



Hab. Whangaroa Harbour (Mr. A. Hamilton). 



This little shell is perhaps near to Barleeia neozelanica,f Suter, 

 while the sculpture, though microscopic, may be compared with 

 Rissoa emarginata, Hutton, a Pliocene form. 



Rissoa insculpta, n. sp. Fig. 28. 



Shell small, elongate, slightly rimate, rather fragile. White. 

 Whorls 5, lightly rounded ; the last whorl much longer than the 

 spire ; the apex minute. Sutures impressed. Sculptured with 

 minute spiral threadlets, absent on the apical whorls, about 

 sixteen on the penultimate, and on the last about twenty-five, 

 of which seventeen to eighteen are in front of the aperture. 

 These are crossed by irregular growth-lines, here and there rather 

 pronounced. Aperture broadly ovate, slightly oblique, and 

 the peristome continuous. Columella regularly curved, lightly 

 thickened and expanded, anteriorly a little produced ; outer 

 lip slightly thickened and projecting from the whorl above. 

 Length, 2-56 mm. ; breadth, 1-35 mm. 



Type in the Colonial Museum. 



Hab. Whangaroa Harbour (Mr. A. Hamilton). 



This form is near to 7?. joveauxiana,% Suter. It differs in 



* Proc. Mai. Soc. London, vol. iii., p. 5, fig. iii. (in text). 



t Proc. Mai. Soc. London, vol. iii., p. 8, fig. v. (in text, on p. 5). 



% Proc. Mai. Soc. London, vol. iii., p. 5, fig. ii. (in text). 



