22 
Rissoa subfusca H u 11 o n. 
North Island: 6, 1 small sp. — 19, 2 sps., h. 2.7. — Auck- 
land Island: 40, many sps., h. 2.2. — 41, Figure 8 Island, under 
stones at low water, many sps. 
Rissoa zosterophila Webster. 
North Island: 6, many small sps. — 21, many small sps. — 
Stewart Island: 36a, many sps., h. 2.5. — Auckland Island: 40, 
4 sps., h. 2. 
Rissoa cylindrella n. sp. 
(PI. I, fig. 14.) 
Shell ovate-cylindric, contorted, fragile, slightly shining, imper- 
forate, white. Whorls 5, appressed in their upper half, then con- 
vex, the last whorl of half the shell height, base rounded; suture 
impressed, margined. Protoconch semiglobose, of 1 1/2 whorl, 
finely spirally striate; subsequent whorls with coarser spiral lirae, 
numerous (about 24) on the last whorl, broader on the base, and 
strong, somewhat flexuous, longitudinal costae, about 18 on the 
last whorl fading below the periphery as well as towards the suture. 
Aperture ovate, sharply angled above; peristome thin, continuous, 
outer lip somewhat produced below, thin, not varicose; columella 
oblique, sinuous; parietal wall with a distinet callus; no umbilicus. 
Dimensions: H. 2.5, br. 1.1 mm. — Locality: North Island: 2, 1 
empty shell. 
Rissoa exerta Suter seems to be the next akin species, but 
differs i. a. in its fewer costae. R. maccoyi T e n i s o n -W o o d s figured 
by Hedley 1900 (pi. XXVI, fig. 11) is very similar but less con¬ 
torted, and its costæ appear to reach the suture. 
Rissoa semen n. sp. 
(PI. I, figs. 10, 11.) 
Shell minute, elongate-ovate, solid, imperforate, polished. Sculp- 
ture varying from entirely smooth to showing traces of spiral striae; 
sometimes a pair of strong revolving keels in the periphery of the 
last whorl and an obscure one on the base. Colour fulvous, some¬ 
what lighter on the aperture side; inner lip reddish orange. Pro¬ 
toconch finely spirally striated. Spire about 1 1/2 the height of 
