134 
that P. bivaricosus , and the other species, herein touched on, do 
not resemble any of the Bulimi of New Guinea so far as known. 
P lacostylus is not known to occur on Norfolk Island ; and con- 
sidering the position of the latter between New Zealand, Lord 
Howe Island, and New Caledonia, with the numerical preponder- 
ance of Placostylus where it is found, we are afforded further food 
for reflection on this important subject. 
It is interesting to note that the geological occurrence of P. 
senilis, Gassies, in the Isle of Pines and Koutoumo Island, New 
Caledonia, is very similar to that of var. senilis at Lord Howe 
Island, in a sand-rock overlying an upheaved coral reef, and 
inferior to the present surface soil of the islands.* 
In the course of these investigations I have been assisted with 
several important suggestions by Messrs. J. Brazier and C. Hedley, 
which have led up to the views enunciated. 
THE LAND AND F RESH- WATER SHELLS OF LORD 
HOWE ISLAND. 
By C. Hedley, F.L.S. 
(Plates xxi. - xxii.) 
In the Memoirs of the Australian Museum, No. 2, “ Lord Howe 
Island,” a sketch will be found on pp. 22 - 30 of the molluscan 
fauna of the island, illustrated by plates 4 and 5, which were, by 
an unfortunate accident, reversed. Stress of professional duties 
has prevented Mr. Brazier from completing this outline by 
detailed descriptions of the species there enumerated, and, greatly 
to the disadvantage of conch ological science, that portion of the 
work dealing with fluviatile and terrestrial shells is now under- 
taken by the present writer. 
On glancing over the species inhabiting the island, the most 
noticeable feature is that they are all endemic, while the absence 
of ubiquitous species like the Truncatelke indicate that further 
search would augment the roll. To the eye of an Australian 
student the types are unfamiliar, and old acquaintances are 
conspicuous by their absence. Here, the operculates are largely 
represented, in Australia they are a foreign intrusive element 
confined to the north-east border, where they increase with every 
degree of latitude as Torres Straits are approached. Neither are 
* Gassies, loc. cit., Pt. ii., p. 67. 
