197 



Tiara semiplicata. Tiara testd ovato-fusiformi, glahrd, longitu- 

 dinaliter plicatd, basi transversim striatd, castaned, a?i/ractibus 

 spircB basi albo fasciatd, anfractu basali fascid submedid alba 

 cincto ; columclld quadrlplicatd : long. -{-J-, lat. -^ poll. 

 Hub. ad Insulam Rieteam. 

 Found on the reefs. 



The basal whorl is only plaited on a comparatively small portion 

 of its circumference, but this is evidently the result of malformation 

 in the only specimen submitted to me. 



Tiara attenuata. Tiara- testd fusiformi, attenuatd, fused, lineis 

 valde elevaiis distantibus cinctd ; columelld triplicatd ^ aperturd 

 albidd, glabrd : long. \^, lat. ^ poll. ..^ivi \^ikU'?' 



Hab. ad Insulam Canam Americse Centralis. 



Found on a rocky bottom at the depth of twenty-eight fathoms. 



Approaching Tiara lineata, but differing from it. The basal whorl 

 of Tiara attenuata is longer in proportion than that of Tiara lineata, 

 and the elevated line on the angular shoulder of each whorl in the 

 former is larger than the others. 



On the paper, " Type 5, 1." 



Genus Conoelix, Swains. 



CoNOELix Virgo. Con. testd conicd, crussd, spirddepressd, lineis 

 tra7isversis subpunctatis insculptd, albidd, columella basi nigro- 

 purpured ; epidermide sub/used, tenuissimd : long. -yV. lat- -['t poll. 



Hab. ad Insulam Rieteam. 



Found on the reefs in shallow water. 



On the paper, " representing Conns Virgo." — W. J. B. 



The following observations by Mr. Swainson elucidate his notes 

 in relation to the Mitres, appended to most of the preceding cha- 

 racters : — 



" To render ray explanation of the notes and references attached to 

 the different species of the Mitruna more intelligible to conchologists, 

 it wiU be necessary for me to state, in as few words as possible, the 

 result of my investigation of this subfamily, and the principles 

 which have regulated these numerical indications. 



" I have already, in another work, characterized the family Volu- 

 tida, which appears to be that primary division of the Carnivorous 

 Gasteropoda {Zoophaga, Lam.;, which represents the Rasorial type 

 among Birds, the Ungulata among Quadrupeds, and the Thysanura 

 among perfect Insects {Ftilota) : these analogies being of course 

 remote, although founded on the structure of the animal, no less 

 than on its testaceous covering. It thus follows that the Lamarck- 

 ian Mitra, instead of a genus, constitute a subfamily, which 

 appears to be the subtypical group of the circle. The five genera 

 composing this circle I have long ago characterized ; and here, for 

 some years, my analysis of the group terminated. The inspection. 

 however, of the numerous species brought home by Mr. Cuming, 

 and the gradually augmented number in my own cabinet, seemed to 



