504 



MOLLUSCA. 



Batli and Bristol, England, surrounded by serpents, changed them by the fervor of her devotion 



into headless stones. Nor were these opinions confined to the 

 mere vul<rar. Wormius described ammonites as petrified ad- 

 ders; Langius considered them to be either the vertebrae of 

 serpents or convoluted marine insects. These notions were 

 not lost on the dealers ; and there are few fossil collections 

 which do not even now possess what is called "a perfect 

 Cornu Afmnonis" that is, an Ammonite with a carved ser- 

 pent's head ingeniously fitted on to the fossil shell. Some 

 learned men considered them as freaks of nature, formed by 

 the plastic power of the earth. The ancients held them in 

 high estimation as very sacred, and of the highest value to the 

 dreamer. At the present day these shells, aside from their use 

 as curiosities for the couchologist and the geologist, serve no 

 other purpose than to increase the volume of the rocks and 

 strata of the earth. But in the age in which these creatures 

 were all living in the sea, swarming by millions, many of them 

 of truly gigantic dimensions, and all of carnivorous and preda- 

 cious habits, what a spectacle of devastation must they have 

 presented ! 



Besides the common form of a convoluted or twisted horn, 

 presented by the extinct animals we have described, there were 



others of different shapes, to which the names of Lituites, Turrilites, <fec., have been given. 



TURRILLITES. 



LITUITES. 



