Nissan Island Mollusca • — Dell 
327 
weaker strength. This sculpture persists across 
the spire whorls, with irregular axial growth 
wrinkles becoming more apparent. On the 
base the fine spirals become somewhat irregu- 
lar but are stronger, and the microscopic 
axials become obsolete. Spire somewhat ele- 
vated. Suture rather impressed. Aperture sub- 
lunate, slightly oblique. Outer lip simple. 
Columella obliquely descending, slightly 
thickened and reflexed, almost covering the 
umbilicus. Umbilicus very narrow, deep, al- 
most covered by the reflected columella. 
Maximum diameter, 3.04 mm.; height, 2.32 
mm.; height of spire 1.0 mm. (Holotype). 
Dimensions of three paratypes, maximum 
diameter 2.64, 3.0, 2.64 mm.; height, 1.91, 
2.36, 1.86 mm.; height of spire 0.73, 1.19, 
0.82 mm., respectively. 
Holotype (M. F. 2511) and two paratypes 
(M. F. 2512) in Dominion Museum, Welling- 
ton, New Zealand. Another paratype in Ber- 
nice P. Bishop Museum, Honolulu. 
Locality: Tangalan Plantation, Nissan Is- 
land, Solomon Islands, under logs. R. K. 
Dell, -6-1944. 
Eustomopsis eustoma Pfeiffer 1856 
A single shell was obtained from Nissan. 
It has the raised spire of erinaceus Pfr. but 
the whole question of the subspecific status 
of the Solomon Island forms needs review. 
Present indications are that Eustomopsis eustoma 
erinaceus Pfr. may be a northern form extend- 
ing to New Ireland with Eustomopsis eustoma 
eustoma Pfr. replacing it in the southern Solo- 
mons. Only extensive series from numerous 
localities can decide the matter. It may well 
be a case of variability with no geographical 
basis. 
Papuina (Pinnadena) periwonensis n. sp. 
Fig. 2 b-d 
Shell trochiform, periphery sharply angled, 
imperforate. Whorls four and a half. Proto- 
conch not clearly marked off from subsequent 
whorls. Apex domed, smooth at first apart 
from fine growth wrinkles. Upper whorls with 
fine irregular incised spirals which are re- 
tained on lower whorls on a narrow band 
below the suture. Penultimate and body whorl 
above the peripheral keel sculptured with 
irregular closely spaced oblique wrinkles. 
Base of body whorl with raised wrinkles, with 
irregular raised spirals running through them. 
Body whorl divided about the middle with a 
strong raised keel. Aperture oblique, ex- 
panded, thickened. Outer lip angled slightly 
by the keel, bearing up to three low broad 
teeth above the angulation. Outer lip ad- 
vanced, columella retracted. No sign of per- 
foration. Colour yellowish cream with broad 
irregular, brown, axially disposed, zigzag 
markings on the spire whorls, becoming 
rather oblique on the body whorl. Outer lip, 
columella and edge of keel white. See Table 
2 for shell measurements. Locality: On veg- 
etation near Periwon Village, Nissan Island, 
northern Solomons, R. K. Dell, May, 1944; 
generally distributed in the area near Tan- 
galan Plantation. 
Holotype (M. F. 2507) and four paratypes 
(M. F. 2508) in the Dominion Museum. 
There is some variation in regard to height- 
width ratios and the brown colour markings 
are less obvious in some examples. Pilsbry 
TABLE 2 
Shell Measurements of Papuina ( [Pinnadera ) 
periwonensis N. sp. 
(Measurements in Millimeters) 
DIAMETER 
HEIGHT 
HEIGHT OF 
SPIRE 
Holotype .... 
28.0 
19.1 
9.5 
Paratype 
27.8 
19.5 
10.2 
Paratype 
26.3 
19.5 
10.7 
Paratype 
27.4 
18.5 
10.1 
Paratype 
25.2 
19.0 
9.2 
(1891) gave Marten’s genus Papuina sub- 
generic rank and used some 15 groups, for 
each of which he gave a short diagnosis. Later 
workers have restored Papuina to full generic 
rank. Iredale (1941: 84) has proposed new 
generic names for 14 of these groups and has 
