193 



Mr. LiGHTFOOT has well defcribed, and given good 

 figures of both thefe niells, in the Pkilofophicai Tranfac- 

 tions of 1780, in which he fiiys, this has three or four 

 white lines, which appear like rays from the central 

 Umbilicus, to difPerent and nearly equidiftant, parts of 

 the circumference. 



We have not, however, yet met with a fpecimen, that 

 had more than three divifions In the body volution, and 

 fometimes one in the fecond whirl, not very diftant from 

 the line of the mouth : polfibly thefe may encreafe with age. 



Thej^/'^a or partitions of the cells do not exaftly accord 

 with Mr. Light foot's defcription : the aperture, or open- 

 ing, in thefe partitions, is indeed triradiated, but ihe fepta are 

 not formed of one piece, but of three fub-triangular plates, 

 each perfeftly diflinft, and unattached to each other. 

 Two of thefe are placed laterally, even with each other, 

 on the fides ; the third is an elevated ridge on the interior 

 volution, Handing before the other plates, and not in a 

 line with them ; but, projefting inwards, gives the open- 

 ing the appearance defcribed in a front view. 



This formation o^ the fcpta is indeed exprefled, by the 

 feftions of the (hell that gentleman has given. 



This very fingular and curious fliell, though different 

 from any known fpecies of Nautilus in the formation of 

 the/cpta, (which are ufually of one, compaft plate, with 



Cc a 



