ROOM IV. COPROLITES OF ICHTHYOSAURI. 375 



spaces of the ribs and sterno-costal arcs of a small Ichthyo- 

 saurus, now in the Oxford Museum. 



"The spaces between these bones are covered with the 

 remains of skin : the epidermis being represented by a delicate 

 film, and the rete mucosum by fine threads of white carbonate 

 of lime : beneath these the corium, or true skin, is preserved 

 in the state of dark carbonate of lime, charged with black 

 volatile matter of a bituminous and oily consistence. Similar 

 black patches of skin are not unfrequently found attached 

 to the skeletons of Ichthyosauri from Lyme Regis, but no 

 remains of any other soft parts of the body have yet been 

 noticed. 



" The preservation of the skin shows that only a short 

 interval elapsed between the death of the animal, and the 

 interment in the muddy sediment at the bottom of the sea, of 

 which the lias is composed." 



There were no traces whatever of a scaly integument, and 

 there is every reason to conclude that the Ichthyosauri had a 

 naked skin, like the Cetaceans. 



COPROLITES. The excrementitious contents of the intestinal 

 canal both of fishes, reptiles, and mammalia, occur in a fossil- 

 ized state : those of the Enaliosaurians are found in great 

 abundance in the lias of Lyme Regis, Street, &c. Before the 

 true nature of these substances was detected and made known 

 by Dr. Buckland, they were called bezoar-stones by collectors. 

 They are often found occupying the abdominal cavity of the 

 skeleton, as in the specimen in Wall-case A, Room IV. (see 

 p. 376.) 1 



The state of preservation of the Coprolites, as these bodies 

 are now termed, is such, as to show not only the nature of 

 the food of the original animals, but also the dimensions, 

 form, and structure, of the intestinal canal ; and from the 

 evidence thus obtained, we learn that these viscera in the 

 Ichthyosaurus were convoluted spirally, as in some of 

 the most voracious existing fishes. In the corresponding 

 organs of Sharks, Dog-fish, (Acanthias,) and Rays, the 

 interior of part of the intestinal tube is spirally coiled ; 

 an arrangement by which the extent of surface of the 

 mucous membrane is greatly increased, and the consequent 



1 See Dr. Buckland's " Bridgewater Essay/' PL XV. 



