SLA. NAT.. 
VOL. XVIIT, No. 2. 
By TOil IRBDALE. 
2y. . 
To locate it in anv of the above families would tend to lose sight 
of it, and cause confusion, and it is a very important little snail. 
In addition to the Hummock Island it has been found on Pearson. 
Island, one of the Investigator Group. 
It has not yet been discovered on the mainland which sug- 
gests that it is a relict form of great age. 
Genus Dipnelix nov. 
Type D. pertricosa sp. nov. PL I, fig. 24. 
Shell small, just reaching 10 mm. in diameter, thin^ spire* 
a little elevated, whorls few, last a little descending, umbilicus 
wide, open, about one third the diameter of shell, mouth a little- 
oblique, a little broader than high, the outer lip rather flattened 
above and swollen below, columella slanting, little reflected, a 
thin glaze connecting across body whorl. Coloration pale brown 
with faint flammules of red brown which generally disappear on- 
the body whorl though sometimes notable in the juvenile stages. 
Whorls four, apical whorls smooth but sculpture develops on the- 
second as very fine radials, which are succeeded by concentric 
lines, later forming with the radials a fine subnodulose sculpture. 
On the penultimate whorls about ten lines can be counted and' 
the fine nodules appear as lozenges: on the last whorl the con- 
centric lines regularly become obsolete so that the reticulation- 
is very faint near the aperture. On the under surface the con- 
centric lines are fairly regular, and the radials obsolete while- 
both become indistinct near the aperture. Breadth 10 mm., 
height 7 mm. Type locality Hummock I. 
One adult and three immature shells from Pearson I. are- 
more boldly colored, the flames being very noticeable, and the- 
reticulation is much more marked so may be called D. p. jlagrans 
subsp. nov. 
Family Charopidae. 
This family includes small shells with a rather distinct radial 
sculpture, flattened appearance, more tightly coiled than the- 
preceding. It is difficult to indicate anything very striking in 
their appearance by words, yet the student very soon recognises 
their affinity at sight. They may be termed helicoid, but not 
conical, commonly discoidal, even with the spfre concave, varying 
from imperforate to very wfldely umbilicate, the sculpture of. 
varying strength, but radials always present.. 
