214 University of Kansas Geological Survey. 



that lie was correct for the most part. The skin of the neck was 

 not necessarily more bagged than that of Varanus, and the 

 sounds uttered by the animals must have been practically such 

 as are uttered by Varanus, since the structure of all the parts 

 here was doubtless the same in both animals. Varanus has a 

 long, forked tongue, and I do not doubt but that the Mosasaurs 

 had such also. 



The Mosasaurs must have been practically helpless on land. 

 They were not sufficiently serpentine, especially Tylosaurus and 

 Platecarpus, to move about on terra firma without the aid of 

 limbs, and these were not at all fitted for land locomotion. 

 That they may have frequented the beaches for the purpose of 

 depositing their eggs is probable, though not certain. They 

 were certainly not viviparous. 



That they were pugnacious in the extreme is very evident 

 from the many scars and mutilations which they suffered dur- 

 ing life. I have observed exostosial growth in their lower jaws, 

 the vertebrae, especially those of the tail, and the paddles, espe- 

 cially the digits. In some the mutilations have been extensive. 

 One tail of a Platecarpus has the spines of the distal half of the 

 tail broken off and false joints produced. Never have I known 

 of a case where there has been evidence of ante-mortem loss of 

 the tail, or any part of it. A paddle of another specimen, fig- 

 ured in part in plate lvi, has the bones of the forearm, carpus 

 and metacarpals all united by exostosis. 



Coprolites which I have always had reason to believe were 

 from these animals are in some places very abundant, weigh- 

 ing from an ounce or two up to a half pound or more. They are 

 ovoidal in shape, with sphincter or intestinal impressions upon 

 them, and contain very comminuted parts of fish bones, fish 

 scales, etc. 



Whether or not they are Mosasaurian in origin, I doubt not 

 that the food of the Mosasaurs consisted almost exclusively of 

 fishes, living or dead, and such small animals as drifted upon 

 the water. Their bones frequently bear the impression of teeth, 

 of post-mortem origin, and in many cases I have found the teeth 

 of small sharks imbedded in them. Invariably, after long ex- 



