INTESTINAL STRUCTURE. 147 



SECTION V. 



INTESTINAL STRUCTURE OF ICHTHYOSAURUS AND OF FOSSIL FISHES. 



From the teeth and organs of locomotion, we come next 

 to consider those of digestion in the Ichthyosaurus. If there 

 be any point in the structure of extinct fossil animals, as to 

 which it should have seemed hopeless to discover any kind 

 of evidence, it is the form and arrangement of the intestinal 

 organs ; since these soft parts, though of prime importance 

 in the animal economy, yet being suspended freely within 

 the cavity of the body, and unconnected with the skeleton, 

 would leave no traces whatever upon the fossil bones. 



It is impossible to have seen the large apparatus of teeth, 

 and strength of jaws, which we have been examining in the 

 Ichthyosauri, without concluding that animals furnished 

 with such powerful instruments of destruction, must have 

 used them freely in restraining the excessive population of 

 the ancient seas. This inference has been fully confirmed 

 by the recent discovery within their skeletons, of the half- 

 digested remains of fishes and reptiles, which they had de- 

 voured, (see PI. 13, 14,) and by the farther discovery of 

 CoproUtes, (see PI. 15,) i. e. of fcecal remains in a state of 

 petrifaction, dispersed through the same strata in which 

 these skeletons are buried. The state of preservation of 

 these very curious petrified bodies is often so perfect, as to 

 indicate not only the food of the animals from which thev 

 were derived, but also the dimensions, form, and structure 

 of their stomach, and intestinal canal.* 



* The following- description of these Coprolites, is given in my me- 

 moir on this subject, published in the Transactions of the Geological 



