GENERA OF SHELLS. 93 



The volutae are distinguished from the mitrse by the 

 lower plaits on the columella being larger than the 

 upper, and by the obtuse and mammellated termination 

 of the spire. 



(a.) Shell ventricose, inflated. (Cymbiola.) 



V. nautica, diadema, armata, ducalis, tessellata. JEthi- 

 opica, melo. Neptuni, cymbium, olla, proboscidalis, porcina, 

 scapha, Brasiliana. 



(b.) Shell oval, spiny or tuberculous. (Muricina.) 



V. imperialis, pellis serpentis, vespertilio, mitis, nivosa, 

 serpentina. 



(c.) Shell oval, subtuberculous. (Musicales.) 



V. hebroea, musica, chlorosina, thiarella, carneola, Guini- 

 aca, laevigata, polyzonalis ? fulva, sulcata, nodulosa. 



(rf.) Shell elongate, ventricose, almost fusiform. (FusoideaJ) 



V. magnifica, ancilla, Magellanica, Pacifica, fulminata, 

 Junonia, undulata, Lapponica, vexillum, valvacea, festiva. 

 mitraBformis, nucleus. 



MARGINELLA. Shell ovate oblong, smooth; 

 spire short ; outer lip with a thickened margin. 

 Aperture subemarginate at base. Columella 

 plaited ; folds subequal. 



The marginellse are smooth, polished shells, and 

 remarkable for the varix on the right lip. They are 

 distinguished from voluta by the equal folds on the 

 columella, by the aperture which occupies almost the 

 whole length of the shell, by the callus on the right lip, 

 and by the scarcely perceptible notch at the base of the 

 aperture. 



(a.) Spire prominent. 



M. glabella, radiata, nubeculata, ccerulescens, quinquepli- 

 cata, limbata, rosea, bifasciata, faba, aurantia, bivaricosa, 



