Williston.] Mosasaurs. 213 



enough to coil about the prey and hold while being forced down 

 the gullet, and the limbs non-prehensile and small, it is seen 

 that, without some peculiar modification of the jaws, food would 

 have been swallowed with difficulty. This peculiar modification 

 is seen in the structure of the joint in the jaws. It has been 

 supposed that the prey, after seizure, was pulled down the 

 throat by the alternate protrusion and fixing of the separated 

 jaws. This, however, could not have been true. The man- 

 dibles in front, while not rigidly connected, yet show ligamen- 

 tous union, and, as we have seen, the quadrates were largely 

 fixed by the pterygoids posteriorly. The jaws, acting together, 

 pulled the prey backward by the lateral bending at the articu- 

 lation, and then both were disengaged after the upper jaw teeth 

 aad the pterygoid teeth had been inserted. Possibly a saurian 

 of the largest size might have swallowed entire an animal as 

 large as a two year-old-calf, but I doubt the possibility. Their 

 food was evidently the numerous small fishes that swarmed the 

 seas with them, with perhaps an occasional animal of their own 

 kind. Possibly this will account for the fact that young Mosa- 

 surs are almost unknown as fossils. 



" The habit of swallowing large bodies between the branches 

 of the under jaw, necessitates the prolongation forward of the 

 mouth of the gullet ; hence, the throat in the Pythonomorpha 

 must have been loose and almost as baggy as a pelican's. 

 Next, the same habit must have compelled the forward position 

 of the glottis or opening of the windpipe, which is always in 

 front of the gullet. Hence these creatures must have uttered 

 no other sound than a hiss, as do animals of the present day 

 which have a similar structure, as, for instance, the snakes. 

 Thirdly, the tongue must have been long and forked, and for 

 this reason : its position was still anterior to the glottis, so that 

 there was no space for it, except it were inclosed in a sheath 

 beneath the windpipe when at rest, or thrown out beyond the 

 jaws when in motion. Such is the arrangement in the nearest 

 living forms, and it is always in these cases cylindrical and 

 forked." The above, by Cope, was written under some misap- 

 prehensions of the true nature of these animals. Still I believe 



