APTYXIELLA. 191 



Family— NERIN^IM]. 



"Shell turrited, sub cylindrical, conical or ovate-elongate, solid, thick; aperture 

 slightly channeled in front. . . . Columella or walls of the aperture furnished 

 with folds, which are continued into the whorls of the spire." — Fischer. 



The author of the ' Manuel de Conchyliologie ' is evidently disposed to agree 

 with Blainville and Woodward in placing the Neringeidge in close relationship to 

 the Cerithiidee rather than to the Pyramidellidge, in accordance with the views of 

 Def ranee and D'Orbigny. The family is almost entirely composed of one genus, 

 Nerinaea (including sub-genera, such as Ptygmatis, &c.) ; but, as if to show that no 

 family can be constituted without an exceptional member, there is just one 

 limited genus which violates the rule as to the existence of internal folds. 



Genus — Aptyxiella, Fischer, 1885, 'Manual,' p. 689; = Pachystylus, 

 Gemmellaro, 1878 ; = Aptyxis, Zittel, 1873. 



Shell conical-elongate, subcylindrical, not umbilicated ; whorls numerous, not 

 embracing. Aperture quadrangular, terminating anteriorly in an insignificant canal ; 

 no internal folds on the columella and walls. 



The above diagnosis is a modification of those given by Gemmellaro and 

 Fischer. The former regards Pachystylus as belonging to the Pyramidellidas ; 

 three species are described by him from the white crystalline Limestone of 

 Montagne del Casale. Fischer gives as an example of the genus Aptyxiella 

 sexcostata, D'Orb., from the Corallian of La Rochelle. 



120. Aptyxiella subconica, sp. nov. Plate XII, figs. 10, 11. 



Description : 



Probable length . . . .55 mm. 



Width about . . . -1th. 



Sprnd angle about .... 10°. 

 Shell elongate, subcylindrical ; whorls numerous, concave, the width of one 

 whorl being nearly equal to its own height, phis that of the preceding whorl. The 

 whorls are apparently smooth, but the available specimens are much worn. 



