AMMONITES. 



not even specific. Ammonoceras is only an accidentally 

 worn portion of an Ammonite, Nothing can of course be 

 known concerning the animal which forms the Ammonite, 

 nor of its habits ; it appears to us a singular circumstance 

 that so many species should abound in all the secondary 

 and in some of the tertiary beds, and yet that no recent 

 species should be known. Lamarck supposes it probable 

 that they may live in the great depths of the sea, and we 

 are much inclined to adopt such a supposition (and to 

 hope that the discovery of recent species will soon reward 

 the exertions of some enterprizing Naturalists,) because 

 we are at a loss to imagine the possibility of their being 

 entirely lost. We know, concerning the Terehratiila, the 

 only other Genus which abounds in all the secondary beds^ 

 and which is there associated with the Ammonites, that 

 some of its species are found' as abundantly in a living as 

 in a fossil state : and we know no reason that the Amino- 

 nites should not be found, since recent Terebratiilce and 

 Trigoni(B which a few years ago were known only in a 

 fossil state, are now to be seen in many collections. 



We have represented three specimens, one to show 

 an Ammonites, another an OrZ>w/i7e.s* according to Lamarck, 

 and the third to show the sinuous and lobated edges of 

 the septa. 



