i6o C O N C H O L O G Y. 



evinces its analogy ; for as the fpires arc 

 few, and greatly recede from each other, 

 it muft follow that the outer fpire will 

 at laft infenfibly fall into a ftrait line 

 or a ftem : and the reafon we never find 

 it with the ftem, prohably, is owing to 

 the thinnefs and brittlenefs of the Shell ; 

 fo that the agitation of the waves, for it 

 is only found caft up on the fhores, eafily 

 breaks off this ftem or cylindric part. PL II. 

 fig. 1 8. is the entire Shell and fig. 19. is 

 cut open, to fhew its chambered ftrufture. 



Genus 3. Turbo Polythalamus five Con- 

 cameratus. I am the firft who has propofed 

 this Genus. It is only found foflil ; and 

 even in that ftate but one fpecies is known 

 to me. It is a turbinated or fpiral Shell, 

 of a produced or lengthened ihape, exa£lly 

 like a Buccinum In appearance, but is con- 

 cameratedorchambered, and the diaphragms 

 or partitions are cut and jagged, like to 

 the foliaceous futures of the Ammonia. 



Cafts 



