94 GENERA OF SHELLS. 



longivaricosa, muscaria, fornicula, eburnea, dentifera, ovu- 



lata. 



(b.) Spire not prominent. 



M. dactylus, bullata, cornea, avellana, persicula, lineata, 

 tessellata, interrupta. 



VALVARIA. Shell cylindrical, convolute ; 

 spire scarcely exserted. Aperture narrow, as 

 long as the shell. Columella with one or 

 more folds at its inferior part. 



Distinguished from nrmrginella by having in general, 

 no varix on the outer lip, which is thin and sharp, 

 though sometimes slight traces of a varix are percepti- 

 ble. They are generally small shells. 



V. monilis, pallida, triticea, oryza, miliacea, bulloides, 

 canaliculata. 



CONVOLUTA. 



Shell icithout a canal, but emarginate or effuse at base; whorls 

 large, compressed, turned in such a manner that the last 

 almost entirely envelopes the others. 



OVULA. Shell inflated, attenuated or sub- 

 acuminated at the two extremities ; mar- 

 gins turned inwards. Aperture longitudinal, 

 narrow, effuse at extremities. Pillar lip, not 

 toothed. 



The ovulse are closely allied to the cyprsea in form ; 

 are sometimes rostrated at both ends, nearly smooth, 

 and have no spire. They are distinguished from them 

 by the left lip never having any indentations, and from 

 bullse by the turning inwards of the right lip. 

 (a.) Outer lip dentate, with folds. 



O. oviformis, angulosa, verrucosa, lactea, carnea, triticea, 

 hordacea. 



