107 



No. 303. I should however suppose it not to be the cast of a chamber, 

 but a disengaged septum ; some of which I have, I believe, from She- 

 pey ; and others, which I have reason to suppose to be foreign. 



Plate XI. Fig. 25, is a minute fossil shell found on the Appennines, 

 near to Sienna, by Thomas Meade, Esq. of Chatley Lodge, near Bath, 

 whose kindness I shall have repeated occasion to acknowledge. This 

 shell appears to be N. crispus, Linn, having lateral spires, with about 

 twenty flexuous crenated joints in the exterior whirl, marked by elevated 

 striae; outer edge caririated ; inferior volutions occult; aperture clasping 

 the body, semicordate, furnished Avith a small perforation or syphon. 

 Testae. Britan. />. 187. Plancus observes, that none of these beauttful 

 fossils are found on the yellow sand of Bologna; but that they are very 

 abundant in the sand of the mountain Covignani, in Rimini. 



To the kindness of the same gentleman I am indebted for the oppor- 

 tunity of laying before you the minute fossil nautilus, Plate XL Fig. 26, 

 which is perhaps one of the species alluded to by Colonel Montague, as 

 a very minute non-descript species, found with the other minute Sienna 

 fossil shells. This is spiral : the inner turns concealed ; the outer turn 

 is wide toward the middle of the shell, where it is umbilicated; but very 

 narrow at the back, and is formed of about fifteen chambers. I have 

 but one specimen of this fossil, and am unable to discover any thing 

 respecting its siphuncle. This shell is more minute than the preceding 

 fossil, and in its general form very much resembles a reduced N. pom- 

 pilius. 



Considering the genus Nautilus of Linnaeus as too comprehensive, 

 and that Nautilus should contain only those spiral multilocular shells, 

 whose inner turns are concealed, and whose siphuncle is obvious; and that 

 Ammonites should include those whose turns are apparent on both sides, 

 but whose siphuncle is concealed ; no genus is left for the reception of 

 those minute shells which were discovered by Beccarius and Plancus, in 



