100 LUCINID^. 



This shell, so remarkable for its universal dispersion, as well in a 

 fossil as in a living state, is not unfrequently thrown upon our ocean 

 shores in such a state as to indicate a neighboring residence. At 

 Nantucket it is far from rare. It is found on every Atlantic shore, 

 even to the Southern Ocean. Vineyard Sound (Dfsor). 



It varies considerably in the development of the lateral teeth, and 

 in the a])proximation of the strige. 



[There can be no douljt that this shell is not the divaricata of 

 Linnajus, as was supposed in the first edition ; tliat name referring, 

 as shown l)y Forbes and Ilanley, to a smaller Eurojjean species. Dr. 

 Stimpson has applied to it — rather unfortunately, I think — the 

 name strig-illa, which had been previously given as a generic name 

 to a group which is sufficiently peculiar to justify a distinguishing 

 name, and which he himself also uses as such. I have rather 

 adopted the prior and more appropriate name of Wood. 



Genus CRYPTODON, TrRTOX. 1822. 



Rounded, thin, nearly equipartite ; valves with a depression bor- 

 dering the hinder end ; a minute cardinal tooth in the right valve. 



Cryptodon Gouldii. 



Fig. 52. 



Shell small, p^lobopc-triangular, white, interior with minute radiating lines. 



Lncina fleruosn, Goni>D, Inv. Mass. 1st ed. 71, fig. .52. 



Crjiptodon flernosus, Adams, Gen. ])1. 114, figs. 2, 2«. 



Liicinn Gonhlii, Philippi, Zcitscli. f. Malak. 1845, 74. 



Tln/aslra Gouldii, Stimpson, Shells of New England, 17 ; Invert. Gr. Manan. 21. 



Cryptodon Gouldii, Stimpson, Check List, 2. 



Shell minute, white, ovate-globose, or somewhat triangular, near- 

 ly equilateral ; beaks prominent, inclined forwards, and having a 

 rounded depression in front of them ; behind them, a re- 

 ^'^.L^^ markable widened groove runs near the margin to the 

 posterior base, producing a deep indentation in the out- 

 line of the margin at that part ; elsewhere regularly 

 c Gouldii i"o^^^^<^Gd ; surface smooth, dead white. Hinge with only 

 2 the vestige of a cardinal tooth, and no lateral ones. Lig- 



ament long and rather large, partly concealed. Interior 

 glossy white, with minute radiating lines. Length, three tenths 

 of an inch ; height, somewhat more ; width, one tenth of an inch. 



