CONCHOLOGY. 135 



- 11. Genus TriVon. PI. XI. 



Animal. As above. - 



Shell. Oval with straight spire and canal, middling generally 

 wrinkled, furnished with varices, rare, scattered, and preserved in 

 longitudinal rows ; aperture suboval, elongated, terminated by a 

 short open canal ; the columellar edge less excavated than the 

 right and covered by a callosity; operculum horny, oval, round, 

 and rather large. Found in the Northern and Mediterranean 

 seas. Thirty-one living species. Three fossil. 



Triton variegatum. Triton tripus. 



T. lampas. T. clavator. 



T. corrugatum. T. chlorostomum. 



T. lotorium. T. subdistortum. 



T. cynocephalum. T. clandestinum. 



T. retusum. T. dolarium. 



T. vespaceum. T. australe. 



T. clathratum. T. Splengleri. 



T. maculosum. T. pileare. 



T. cutaceum. T. pigrum. 



T. undosum. T. canaliferum. 



T. nodiferum. T. tuberosum. 



T. scorbiculator. T. anus. 



T. succinctum. T. cancellatum. 



T. femorale. T. rubecula. 



T. tranquebaricum. 



FAMILY XVITI. 



Alita. Three genera. 



1. Genus RosteUaria. PI. XI. 



Ardmal. Entirely unknown. 



Shell. Subdepressed, turriculated, with a produced and 

 pointed spire ; aperture oval on account of a rather larg« excava- 

 tion of the columellar edge, the right margin dilating with age 

 and having a sinus contiguous to the pointed canal which ter- 



