SECTION VIII. 165 



work. Gualtleri has alfo figured it as 

 magnified by the microfcope in Tab. 19. 

 fig. H. I. and Linnaeus ranks it among 

 the Nautih. 



It is very remarkable, that this recent 

 fpccies is a diftindt kind from any of the 

 foffil ones known. It not only differs in 

 particular circumftances, but even in an 

 eflential charader ; which is, that as all 

 the fofiil ones, or Ammonitae, have a con- 

 cave center, this recent kind has a very 

 prominent or projefting one. 



By what general obfervations I have 

 made on the Ammonite, I think the fpe- 

 cific charafter for their fefllons, or arrange- 

 ments, is to be taken from the w^ork on 

 the back of their fplres ; for it is the 

 moft obvious, conftant, regular, and cer^. 

 tain charafter. 



On this character I fhall divide the Am- 

 monia into eight fections or arrangements. 



M 3 I have 



