OP CONCHOLOGY. 



211 



DESCRIPTIONS or MARINE GASTEROPODiE, INHABITING 



POLYNESIA. 



\ BY W. HARPER PEASE. 



MITRID^. 



MiTRA ASSiMiLis, Pease. — Plate 15, fig. 1. 



Description. — T. fusiformi, crassa, sollda, basi subtruncata, 

 laevigata, striis remotis, punctatis, cingulata, ad basin sulcata ; 

 spira brevis ; labro crenulato ; columella quadriplicata ; rufo- 

 castanea, linea unica aut fascia flavescente, infra suturam, cinc- 

 ta, apertura pallide purpurea. 



Dimensions. — Long. 17, diam. 6J mill. 



Shell fusiform, solid, thick, base somewhat truncate, smooth, 

 encircled with rather distant punctured striae ; spire short ; lip 

 crenulated on its edge ; columella four-plaited ; reddish-chest- 

 nut, encircled with a single yellowish line or band a short dis- 

 tance below the sutures ; aperture light purple. 



Remarks. — Allied to M. coronata. There is not, however, 

 the slightest evidence of crenation at the sutures, and it is found 

 associated with the typical coronata at several localities. My 

 collection comprises an extended series of the latter species, in 

 which the variation chiefly extends to size, prominence of the 

 crenation, and in being more or less blotched or spotted with 

 white. They are all more or less roughened longitudinally by 

 coarse irregular striae. 



The description in Conchologia Iconica should be made to con- 

 form with that of Lamarck, as regards the transverse striae. 



Genus MITROPSIS. 



T. fusiformi, longitudinaliter plus minusve costata seu plicata ; 

 apertura angusta ; labro dentato, superne sinuato ; columella 

 plicata, callo marginata. 



