96 GENERA OF SHELLS. 



TEREBELLUM. Shell convolute, subcylin- 

 drical, summit acute ; aperture longitudinal, 

 narrow above, emarginate at base. Columella 

 smooth, truncated inferiorly. 



The terebellum has no epidermis ; it is thin, smooth 

 and when we look at its back, appears to be irregularly 

 notched at the base. It most resembles the ancillaria, 

 oliva and conns, and has a slight likeness to the young 

 cypraea. 



T. subulatum, convolutum, fusiforme. 



ANCILLARIA. Shell oblong, subcylindrical ; 

 spire short, not channelled at sutures. Aper- 

 ture longitudinal, scarcely emarginated at base, 

 effuse, a callous, oblique varix at base of col- 

 umella. 



The ancillaria greatly resembles the oliva, but 

 the upper edges of the whorls of the spire rest, 

 each of them, against the preceding whorl and are not 

 separated by a spiral canal, as in oliva. The callous, 

 oblique varix distinguishes this genus from terebellum 

 and buccinum. The aperture is longitudinal, but never 

 extends the whole length of the shell. 



N. cinnamonea, ventricosa, marginata, Candida. 



OLIVA. Shell subcylindrical, convolute, 

 smooth ; spire short, sutures channelled. 

 Aperture longitudinal, emarginate at base. 

 Columella obliquely striate. 



O. porphyria, textilina, erythrostoma, pica, tremulinay 

 angulata, maura, sepulturalis, fulminans, irisans, elegans,. 

 episcopalis, venulata, guttata, leucophaea, reticularis,, flam- 



