COPROLITES. 151 



Among living voracious reptiles we have examples of 

 stomachs equally capacious; we know that whole human 

 bodies have been found within the stomachs of large Croco- 

 diles; we know, also, from the form of their teeth, that the 

 Ichthyosauri, like the Crocodiles, must have gorged their 

 prey entire ; and when we find, imbedded in Coprolites de- 

 rived from the larger Ichthyosauri, bones of smaller Ich- 

 thyosauri,, of such dimensions, (see PI. 15, Fig. 18. And 

 Geol. Trans. 2, S. vol. iii., PI. 29, Figs, 2, 3, 4, 5,) that the 

 individuals from which they were derived, must have mea- 

 sured several feet in length ; we infer that the stomach of 

 these animals formed a pouch, or sac, of prodigious size, ex- 

 tending through nearly the entire cavity of the body, and of 

 capacity duly proportioned to the jaws and teeth with which 

 it co-operated. 



Spiral Disposition of Small Intestines, 



As the more solid parts of animals alone, are usuallj 

 susceptible of petrifaction, we cannot demonstrate by direct 

 evidence the form and size of the small intestines of the 

 Ichthyosauri, but the contents of these viscera are preserved 

 in such perfection in a fossil state, as to afford circum- 

 stantial evidence that the bowels in which they were 

 moulded, were formed in a manner resembling the spiral 

 intestines of sdme of the swiftest and most voracious of our 

 modern fishes. 



We shall best understand the structure of these intestines 

 by examining the corresponding organs of Sharks and 

 Dog-fish, animals not less peculiarly rapacious among the 

 inhabitants of our modern seas, than the Ichthyosauri were 

 in those early periods to which our considerations are car- 

 ried back. We find in the intestines of these fishes, (see 

 PI. 15, Figs. 1, and 2,) and also in those of Rays, an ar- 

 rangement resembhng that of the interior of an Archimedes 

 screw, admirably adapted to increase the extent of internal 



