108 LIMN AIDA. 
BRONDELIA, Bourg., 1860. Apex more minute than in the type, 
sinistral, with a persistent spiral nucleus. Terrestrial, living on 
humid rocks in the forest of Edough, Boue (Algeria). 
Latta, Gray, 1849. 
Distr.—2 sp. New Zealand. Fossil, 1 sp. Eocene; Idaho. 
L. neritoides, Gray (ciii, 39). 
Shell ancyloid, with subspiral summit ; the interior is provided 
posteriorly with a semicircular transverse ledge or plate, attached 
to the shell on the left, turned up and notched on the right side. 
Animal with elongated foot, well distinguished from the 
mantle ; eyes external to the tentacles; no jaw? Central tooth 
bicuspid, laterals unicuspid, marginals tricuspid. 
GunpLacHtA, Pfeiffer, 1849. 
Dedicated to Dr. Gundlach, a distinguished Cuban concholo- 
gist. 
Syn.—Poeyia, Bourg., 1860. 
Distr.—5 sp. United States, Cuba, Tasmania. Fossil. Basin 
of Mayence. Pliocene; W. Indies. G. ancyliformis, Pfr. 
(ciii, 40). 
Shell very small, thin, obliquely conic, apex inclined poste- 
riorly and to the right ; base two-thirds closed by a flat, straight- 
edged shelf, leaving a semicircular aperture. 
Radula; central tooth bicuspid, laterals and marginals multi- 
cuspid. 
Poeyia was described from a young Gundlachia without 
septum; on the other hand the young of Ancylus textilis, Guppy, 
of Trinidad, are sometimes provided with a septum, sometimes 
without it; so that the presence or absence of the septum is not 
always a sure means of distinguishing the genera. 
AcrocHASMA, Reuss, 1860. 
Distr.—A. tricarinatum, Reuss (cii, 94), from the fresh-water 
limestones (Miocene) of Bohemia. 
Shell trilateral, pyramidal, rounded below in its whole ampli- 
tude, with one posterior coneaye, and two lateral slightly convex 
planes, ending upwards in an acute reflected apex, beneath with 
a longitudinal aperture through the shell, which in its living 
state appears to have been covered with an epidermis. It may 
be considered as a fresh-water representative of the marine genus 
Puncturella. 
This, and the genus Valenciennesia, previously described, may 
belong to the family Siphonariidee. 
Susorper THALASSOPHILA. 
Head a dilated disk without distinct tentacles, the eyes sessile 
on its upper surface; pulmonary pouch protected by a valvular 
