10 CYLICHNIDyE. 



St/n. Bullina, liisso, not Firm. Cylindrella, Swains., 



not Vfeiff. Volvaria, Brown, not Lam. 



Ex. C. cylindracea, Pennant, pi. 56, fig. 6. Shell, 

 C. cylindracea, fig. 6, a. 



The capital disk in Cylichna is greatly elongated, and 

 the eyes are sessile near its middle ; the shells have the 

 spire completely concealed or involute, so that the apex 

 appears as if perforated, the last whorl is usually cylin- 

 drical and convolute, and there is a conspicuous fold on 

 the fore part of" the inner lip. The species are chiefly 

 from deep water, and are world-wide in their geographical 

 distribution, being found in the Northern and European 

 Seas, the Philippines, Australia, and North America. 



Species of Cylichna. 



alba, Brown. labiosa, Phil. 



araclns, Quoy and Gaim. nitidula, Loven. 



biplicata, A. Adams. occulta, Migh. 



brevissiraa, A. Adams. pygmrea, A. Adams. 



concentrica, A. Adams. pyramidata, A. Adams. 



concinna, A. Adams. Sarsii, Phil. 



couulus, Desh. strigella, Loven. 



corticata, Moll. teres, Phil. 



cylindracea, Perm. triticea, Couth. 



decussata, A. Adams. umbilicata, Mont. 

 involuta, A. Adams. 



Sub-gen. mnestia, H. and A. Adams. 



Shell ovately cylindrical, marbled or banded, transversely 

 striated ; spire conspicuous, immersed in the deep umbilicus of 

 the apex ; aperture narrow, acuminately produced both above 

 and below. 



bizona, A. Adams. marmorata, A- Adams. 



