372 Mr. Broderip and Mr. G. B. Sovverby on some 



Natica pallida. 



J\. testd subglobosd, albidd, tenui, apice breviter acuminata, eroso ; 

 anfractibus rotundatis, margine elevatiusculo, suiurd distinctd ; 

 umbilico parvo ; long. 1^^^, lot. 1, poll. 

 Hab. in Oceano Arctico. 



From Icy Cape. A very thin horny epidermis covers the outside of 

 this shell, which is eroded at the apex, like many others from the same 

 locality as well as several from Melville Island, the coast of Newfound- 

 land, and other arctic regions, 



Natica Otis. 



M. testd obovatd, spird brevissimd, acuminatd, pallidd, umbilico magna 

 calloque umbilicali purpurascenti-nigricantibus ; long. l^V? ^^t- ^j 

 poll. 

 Hab. ad littora Oceani Pacifici . 



In general form this species nearly resembles JV. melanostoma, but is 

 at once distinguished by its solidity. The inside of the aperture is purple 

 brown. From Mazatlan. 



*Natica clausa. 



.A'", testd subglobosd, anfractibus ventricosis, sup&rnk subdepressis, mar- 

 gine elevatiusculo ; umbilico clauso ; long. \%, lat. ^, poll. 

 Hab. 



The umbilical callus completely covers the umbilicus. Operculum 

 testaceous, rather thin and somewhat concave. In Mr. Sowerby's col- 

 lection. 



MiTRA CRASSIDENS. 



M. testd fused, ovato-fusiformi , spird mediocri ; suturd simplici ; 

 anfractu ultimo subventricoso, medio subdepresso, ad basim sub 

 recurvo ; columelld A-plicatd, plicis tribus superioribus crassis, 

 inferiore sub-obsoletd ; epidermide crassd, fused ; long. 2-^^^, lat. 



y%, poll. 



The sub-recurved base is coarsely striated. In the young shells the 

 epidermis is comparatively thin, and the base of the body- whorl is not 

 recurved. 



