154 INTESTINAL STRUCTURE 



surface remains almost the same, as if they had been cir- 

 cular. Had a large expansion of intestine been superadded 

 to the enormous stomach and lungs of the Ichthyosaurus, 

 the consequent enlargement of the body would have di- 

 minished the power of progressive motion, to the great 

 detriment of an animal which depended on its speed for the 

 capture of its prey. 



The above facts which we have elicited from the copro- 

 litic remains of the Ichthyosauri, afford a new and curious 

 contribution to our knowledge both of the anatomy and 

 habits of the extinct inhabitants of our planet. We have 

 found evidence which enables us to point out the existence 

 of beneficial arrangements and compensations, even in those 

 perishable, yet important parts which formed their organs 

 of digestion. We have ascertained the nature of their food, 

 and the form and structure of their intestinal canal; and 

 have traced the digestive organs through three distinct 

 stages of descent, from a large and long stomach, through 

 the spiral coils of a compressed ilium, to their termination in 

 a cloaca; from which the Coprolites descended into the 

 mud of the nascent lias. In this lias they have been interred 

 during countless ages, until summoned from its deep recesses 

 by the labours of the Geologist, to give evidence of events 

 that passed at the bottom of the ancient seas, in ages long 

 preceding the existence of man. 



Intestinal Structure of Fossil Fishes. 



Discoveries have recently been made of CoproUtes de- 

 rived from fossil fishes. Mr. Mantell has found them within 

 the body of the Macropoma Mantellii, from the chalk of 

 Lewes, placed in contact with the long stomach of this 

 voracious fish : the coats of its stomach are also well pre- 

 served.* Miss Anning also has discovered them within 



* See Mantell's Gcol. of Sussex, PI. 38. I learn from Mr. Mantel!, 



