PART 11. LUCERMN^. 329 



Discodoma Sw. Teeth none ; aperture angulated ; 

 the inner lip nearly obsolete, the outer only slightly 

 thickened ; margin carinated. 

 albilabris. Chem. 125,f. 1090, Gualteriana. Chem. 5. vig. 



1091. 44. a—c. 



inflata. lb. 126. f. 1100, 1. marginata. lb. 102. f. 1095. 

 gigas. lb. f. 2044, 5. angistoma. lb. 125. f. 1092. 



Lucerna Humph. Outer lip with teeth, either mar- 

 ginal or internal ; the outer lip thick and reflected ; 

 circumference carinated. 

 acutissima. Zool. 111. ^ ii. fasciata Guild. Bow. Conch. 



pi. 96.* ' 7. f. 23. 



lanx. En. Meth. 462. f. 2. fulgurata Sow.f 

 lychnuchus. Ch. 126. f. 1108. sinuata. Chem. 126. f. 1110 



— 1102. (Aberrant.) 



Anastoma Lam. Aperture turned upwards, furnished 

 with plaited teeth on both sides. 



A. depressa. Chem. 109. f. 919, 920. 



Lucidula Sw. Aperture transverse ; both lips much 

 thickened and united ; the outer with marginal obso- 

 lete teeth at the base ; umbilicus closed. 



' Barbadensis Lam. No. 49. p. 78. Fer. Moll. pi. 47. 2, 3, 4. 



LucERNELLA Sw. Teeth on both sides of the aper- 

 ture ; surface regularly and distinctly striated. Cir- 

 cumference convex.:}: 



Polydontes Montf. Aperture nearly circular, sur- 

 rounded with obtuse tubercular teeth. 

 P. imperator. Bowdich, Elem. of Conch, pi. 7. f. 21. 



Lyrostoma Sw. Aperture lyre-shaped, very contracted 

 near the body-whorl, widened beyond. 



L. labyrintha. Chem. pi, 208. f. 2048. Lam. p.46. 



* The original figure of the shell and animal given in Zool. 111. is 

 copied by Ferussac, Guerin, and numerous others, but so badly, that the 

 shell appears to be a totally different species. 



f Mr. Sowerby has published a very beautiful detached plate of this 

 species, first described by himself. 



X Some slight variation has been made in the arrangement of this group 

 from that previously stated at p. 193. Cyclodoma is here united to Luccr- 

 nella, and the new sub-genus Lyriostoma proposed. 



