189 



and to a fpecimen fent at the fame time, (which we con- 

 fider as the N. Calcar,) there was nothing in appearance 

 like the figure of the A^. Icevigatulus, which is neither de- 

 fcribed or figured as carinated. 



Nautilus Calcar Lin. Syji. p. 1162.— Gmel. Syfi. p. 3370. 2. Calcar. 



Turt. hm. iv. p. 306. Tab. 15. f. 4. 



Martini Conch, t. 20. f. ISO. ISI ? 



Walk. Min. Shells, f. 66 ? 



Adams Microfc. p. 641. t. 14. f. 31 ? 



N. with a fmooth, fpiral fliell ; with fix joints on the 

 body whirl, marked by as many flexuous elevated fi;riae, 

 radiating from the centre, but not quite extending to the 

 margin : back fl:rongly carinated: both fides equally con- 

 vex, fmooth, and rather more elevated in the middle : in- 

 terior volutions lofl; after entering the aperture, which is 

 femi-cordate, clafping the body equally on both fides, 

 and furnifiied with a fmall perforation. 



It is perhaps very difficult to determine which of the 

 various fpecies, given by diffeient authors for the A^. Calcar 

 of Linn ^ us, is the real fiiell : Gmelin quotes two figures 

 in Martini, that appear perfeftly diftinft, vol.i. tab. 19^ 

 fig. 168. 169. the firfl; of which is fmooth on the back ; the 

 other is not only flrongly carinated, but furnifhed with 

 fpines on that part. The fame figures alfo occur in 

 GuALTiERi, t. ig. B. C. and are equally referred to by 

 Gmelin: that we have quoted in Martini forourdiell, 

 js indeed with doubt, for in all we have examined, the 



Carina^ 



