18 THE NAUTILUS. 
zone. Surface under a lens presenting a roughish appearance, caused 
by granules elongated in the direction of lines of growth. 
Spire depressed, slightly convex ; apex obtuse. Whorls 
4, gradually widening, the last depressed; deeply and 
abruptly descending to the aperture, rounded at the 
periphery, very strongly constricted behind the peristome. 
Aperture very oblique, nearly circular; lip narrowly ex- 
panded, flattened, white, upper and lower margins continu- 
ous across the parietal wall, the basal margin slightly 
thickened within. Umbilicus deep, rather narrow. 
Height 3, diam. 7 mill. 
Habitat New Guinea. 
This species is allied to H. tuckeri Pfr., but may readily be dis- 
tinguished from that species by the continuous peristome, more 
oblique aperture and deeper constriction of the whorl behind the 
lip. 
The type specimen was received from Mr. Gro. W. DEAN, of 
Kent, Ohio, to whom it was presented by the sons of Wm. DENTON, 
a devoted naturalist who lost his life while pursuing his researches 
in the interior of New Guinea. 
NOTE ON THE DISTRIBUTION OF HELICINA OCCULTA. 
BY CHARLES R. KEYES. 
This operculate land shell was first described in 1831, by Say, 
from fossil specimens; and it has been only quite recently that liy- 
ing examples have been found. Thespecies is a characteristic fossil 
of the loess (post-pleiocene) of the Upper Mississippi Valley ; and is 
widely distributed over this region. It is found abundantly in the 
post-pleiocene deposits of central and eastern Iowa and portions of 
Illinois, while it occurs less plentifully in similar depositions along 
the Missouri river. Like the large majority of loess fossils of the 
region this form is strikingly depauperate, evidencing, as first pointed 
out by Megee and Call,* a great diminution of vitality, doubtless 
due, in great part at least, to a much lower temperature than at pres- 
ent. All the shells from the loess present a peculiar chalky white- 
ness which renders them easily distinguished from “dead” shells of 
the same species still living. More than thirty species of land and 
fresh-water mollusca are now known from this deposit in Iowa; and 
* American Jour. Sci., Vol. xxiv, Sept., 1882. 
