304 



and was classed with the G. Nautilus by Linnaeus. 

 Peron has discovered that it is attached at the lower 

 part of the animal to which it belongs, and, except a 

 portion of its last spiral turn, is completely enveloped 

 by the body of the animal. 



Spirula Peronii. 



SPIROLINITES — A fossil species. 



LITUOLITES.— Ditto. 



RENULITES.— Ditto. 



CRISTELLARIA. 

 The greater number of these shells, of which the Nau- 

 tilus Planatus is the type, are microscopic, and figured 

 and described by Fichtel, also in the Encyd. Method 

 (Cristellaria Planata) &c pi 467,/ 1, A. B. C. 



Nine species are enumerated by Fichtel, all of which 

 appear to be recent shells. 



