118 



or seven fossil shells, all fresh water species, imbedded 

 in company with the bones. 



Dr. Gould presented the following descriptions of new 

 species of shells, brought home by the U. S. Exploring Ex- 

 pedition : 



Trochus tantillus. Testa minuta, conico-discoidea, flavido 

 cinerea, lineis radianlibus flexuosis fuscis picta : spira depressa 

 anfr. 4-5 angulatis, ultimo ad peripheriam dilatato, acuto : basis 

 convexiuscula, perforata, flavida, liris duabus concentricis pro 

 clivibus munita: apertura obliquissima. Axis -^^, diam. | poll 

 Hah. Sandwich Islands. 



I have met with no description of a species so small as this 

 and yet its characters are very prominent. Its form and concen 

 trie ridges give it the aspect of a conical operculum. 



Planaxis lineolatus. Testa minuta, solida, acuto-conica, 

 ex albido fuscescens, lineis castaneis numerosis cincta: spira 

 acuta, anfr. 6-8 planulatis, supernis granulatis, ultimo f testse 

 longitud. fequante, ad peripheriam sub-angulato : basis spiraliter 

 striata: apertura rotundato-ovata, postice baud callifera; labro 

 pallido,vel fusco tessellato, intus denticulato; fauce fusco. Axis ^, 

 diam. ^ poll. Hob. Wilson's Island. 



This little shell is not infrequent in cabinets, but I find no de- 

 scription of it. 



Pyramidella ambigua. Testa minuta, albida, imperforata, 

 ovato-subulata, costis longitudinalibus exilibus ad 20 ornata, inter- 

 vallis spiraliter striatis : spira acuta, anfr. ad 10 planulatis : aper- 

 tura auriculata, antice subefFusa ; columella callosa, gibbosa, an- 

 tice sinuata ; labro simplici, incrassato. Axis J- ; diam. j\j- poll. 

 Hob. Clermont Tonnere Island. 



The characters of this little shell, which I have for the present 

 placed under Pyramidella^ are somewhat abnormal. Its size and 

 sculpture would suggest Truncatella ; its aperture is somewhat 

 like the effuse form of Eidima ; the form of aperture is also like 

 Pyramidella, though it has no proper plaits, but merely an intru- 

 sion of callus with an adjacent sinus in place of them, and in 

 this, is like Monotigma. 



Cerithium (Potamis) sacratum. Testa rudis, elongata, badia 



