108 LIMN^IDiE. 



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). 



Latia, 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. 



GuNDLACHiA, 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, Rcuss, 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 concave, 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 Siphonariidse, 



Suborder THALASSOPHILA. 



Head a dilated disk without distinct tentacles, the eyes sessile 

 on its upper surface ; pulmonary pouch protected by a valvular 



