Zoological Society. 69 



patterns presented by those recent Avicula that inhabit shallows 

 and moderate depths. 



Aviculo-pecten intercostatus and elongatus also exhibit markings. 



Spiri/er decorus and Orthis resupinata, show fine radiating white 

 lines. 



Terebratula hastata, with radiating stripes. 



The analogy of any existing forms that can be compared with 

 those enumerated, would lead to the conclusion that the markings 

 in these instances are characteristic of mollusks living in a less 

 depth of water than 50 fathoms. In the case of the TerebratulUj 

 which belongs to a genus the majority of whose living representa- 

 tives inhabit deep water, it may be noticed that all the living spe- 

 cies exhibiting striped shells are exceptions to the rule, and come 

 from shallow water. 



There are many circumstances which warrant us to suspect that 

 the carboniferous mountain limestone of most regions was a deposit 

 in shallow water. The facts now adduced materially strengthen 

 this inference. 



In the British Museum there is a beautifully spotted example of a 

 Devonian Terebratula, brought by Sir John Richardson from Boreal 

 America. 



Specimens of the Turbo rupestris] from the Lower Silurian Lime- 

 stone of the Chair of Kildare near Dublin, exhibit appearances that 

 seem to indicate sj)iral bands of colour. . 



ZOOLOGICAL SOCIETY. 



November 9, 1852.— J. S. Bowerbank, Esq., F.R.S., in the Chair. 



Descriptions of a new genus, and of several new species, 



of mollusca, from the cumingian collection. 



By Arthur Adams, F.L.S. etc. 



Family Solenellid^. 



Animal oblong. Mantle open in the entire length ; margin 

 double, outer edge fimbriated ; hind outer edge ending in two cal- 

 lous conical processes immediately below the respiratory orifice. 

 Respiratory orifice continuous with the opening of the mantle, the 

 margin fringed ; anal siphon simple-edged, tubular, elongate, muscu- 

 lar, produced beyond the fringed mantle-margin which surrounds its 

 base. Gill single on each side, attached the whole length. Labial 

 palps elongate, fringed at their margins, and surrounded at their base 

 by a thin dilated membrane. Foot large, compressed, geniculate, 

 ending anteriorly in a folded ovate disc with crenate margins. 



Shell thin, not pearly within. Hinge-margin with comb-like 

 teeth. Ligament external. 



Genus Neilo, A. Adams. 



Testa transversa eequivalvis, incequilateralisy epidermide fusco 

 tenui indiita, latere postico Mans. Dentibus cardinalibus^ 

 nullis, lateribus anticis et posticis plurimis in serie rectiusctda 



