AMMONITES — ZOOLOGICAL, ETC. 



99 



We cannot refrain from noticing, in conclusion, the inser- 

 tion of the first paper on " Geology applied to Civil Engineer- 

 ing,^' in our present work, and which will be followed, from 

 time to time, by others bearing on the same point ; we do so 

 in the hope of giving greater publicity to our views, as to 

 rendering the science of Geology popular on account of its 

 utility, as well as interest, and to solicit the co-operation of 

 all persons whose employments may enable them to make 

 observations connected with this subject. 



THE EDITOR^ 



ORIGINAL COMBIIJHiGATIONS. 



Ammonites Zoologically and Geologically considei'ed. 



(Continued from p. 83.) 

 INTERNAL CHARACTERS OF AMMONITES. 



Every Ammonite is composed internally of a greater or 

 less number of Sef)ta, succeeding each other in regular order 

 in several whorls of the spire ; and, beyond these, of an open 

 space, always occupying about two thirds of the last whorl. 

 All Zoologists are agreed as to the functions of this large 

 cavity superior to the Septa, destined to contain the animal. 



Functions of the Septa. — Nothing is more simple than the 

 functions of the Septa amongst the Ammonites and all other 

 chambered shells. When we see them so complicated in struc- 

 ture, we are tempted to attribute to them great importance 

 in the animal economy, whilst they are only analogous to 

 the air bladders of fishes. As I have elsewhere remarked,(l) 



(]) Histoire generale et particuliere des Cephalopodes acetabuliferes. 

 Introduction, and at the article Belemnites of the Paleontologie Fran- 

 9aise, p. 24. 



H 2 



