CYLICHNA. 221 



front, by the curvature of the inner lip ; occasionally the lip is a 

 little waved inwards at the middle, narrowing- the aperture ; at the 

 region of tlic nnil>ilicus is a llattened, white space, thickened by en- 

 amel, gradually disa})pcaring within the aperture ; the whole inner 

 margin is sometimes slightly coated with enamel. Length, one 

 fourth of an inch ; l)readth, one tenth of an inch. 



Found ])lentifully in the maws of fislies taken in Massachusetts 

 Bay. Connecticut (^Linslcij) ; Grand Manan {^Stu}ij)son) ', Maine 

 (Mt'o^hels) ; Greenland (Mdrch) ; Fishing Banks {Wi/lis). 



This shell is analogous to the Bulla cylindracca of Pennant {Brit. 

 Zool. pi. 70, fig. 85). But that is a much longer shell, and de- 

 cidedly umbilicated in the region of the spire. Brown figures a 

 shell under the name of Volvaria alba ( Conch, of Great Brit., <fec., 

 pi. 38, figs. 43, 44), which bears a striking resemblance to this 

 shell. [It is now considered identical. 



Cyliclina oryza. 



Fig. 93. 



Shell minute, Avhite, ,e;lossy, sub-oval, last whorl enveloping all the others, and 

 marked with a few revolving lines; summit depressed, imperforate. 



Bulla oryza, Tottex, SilHrnan's Journ. Old Series, xxviii. 350, fig. 5 (1835). — Gould, 



Inv. 16S, fig. 93. — 1)e Kay, N. Y. Moll. 18, pi. 31, fig. 327. 

 Cylkhna ori/za, Stimpson, Check Lists, 4 (1800). 



Shell not very small, not very thin, translucent, white, regularly 

 diminishing from tlie middle towards each end, the tip being de- 

 pressed into a shallow pit, and the front being rather pointed ; 

 last whorl enclosing all tlic others ; surface marked with mi- 

 nute lines of growth, a few revolving lines on the anterior 

 portion, and a few more obscure ones near the shoulder, none 

 of them percei)tible without a magnifier. Aperture as long '""•'''''' 

 as the shell, narrow behind, and widening forwards ; outer lip sim- 

 ple and sharp, commcneing beyond the axis of the shell, and rising 

 a little, tlien turns, and passes forwards by a regular curve ; the 

 left margin is thickened and forms a smooth, glossy pillar, whicli is 

 twisted so as to form an oblique fold ; at the base it terminates 

 abruptly, so as almost to form an ol)tuse tooth ; a thick callus, com- 

 mencing at the junction of the outer lip, runs round wdthiii the 

 whorl, giving strength to the region of the spire. There is no um- 

 bilical opening either at the tip or base. Length, three twentieths 

 of an inch ; breadth, one tenth of an inch. 



