On new Species of Mollusca. 439 



towards the north the size diminishes. The maximum of 

 one group, liowever, surpasses the minimum of another 

 group. When such is the case, the variation in size seems 

 also to form a continuous series, which, I am sure, will prove 

 still more continuous when further material is obtained. 



Althouo-h the distinguishing characteristics derived from 

 size also are thus rendered unimportant, the variation of the 

 weasel certainly does not lack significance, because inter- 

 mediate stages occur which unite the extreme forms. 



LIX. — New Species of Mollusca of the G^enem Vol uta, Conus, 

 Siphonalia, and Euthria. BjG. B. Sowerby, F.L.S. 



[Plate XI.] 

 The types are in the British Museum (Natural History). 



1. Voluta um'ph'cata, sp. n. (PI. XI. fig. 1.) 



Testa fusiformis, tenuis, pallida, utrinque acuminata, iu medio eou- 

 vexa ; spira pj'ramidata, mediocriter louga ; sutm-a anguste 

 canaliculata ; aufractus (5-6 ?), supra breviter concavo-depressi, 

 delude convexi, undique longitudinaliter filo-striati, spiraliter 

 dense decussatim striati, plicis longitudinalibus numerosis, iu 

 ultimo subobsoletis instnicti ; aufractus ultimus oblongus spiram 

 multo superans, supra obtusissime angulatus, supra augulum sub- 

 planato declivis, infra convexus, basim versus attenuatus ; aper- 

 tura ampla, fauce uitens, rufo-carnea ; labrum tenue vix reflexum ; 

 columella tenuis, plica unica alba leutissirae contorta instructa ; 

 area polita columellari late eft'usa, rufo-aurantia. 



Long, (circ.) 200, maj. diam. 82 mm. 



Bab. Japan. 



I have seen only one shell of this remarkable species ; the 

 apex is unfortunately broken off, so that the description is 

 necessarily incomplete, although the shell is otherwise in 

 perfect condition. It is of a light structure, sculptured with 

 close spiral stria, which are more prominent on the upper 

 part of the whorls ; the whorls of the spire are closely and 

 regularly longitudinally plicate, but the plicaj become irre- 

 gular and almost obsolete on the body- whorl. The whole 

 interior, including the lip, is lustrous pinkish red, and a thin 

 shining enamel of orange-red covering the columella is spread 

 half across the whorl. The columella is furaished with a 

 single well-defiued plait, whicli is long, narrow, and but 



