iro KANSAS UNIVERSITY QUARTERLY. 
Clidastes. Platecarpus. Tylosaurus. 
CONC rca ites TIES tt a eae ere ry Fe ge Se anc a / yh a 
AR Tikianelsietice Sabie iene aK OMe Ug SRE Ce ra R37 13? 
PUURIMRTOCICMmen i cnah nie y Tin wenn Mlcriine yor) wae ny 9 10 
PRY RP CAL GAUSars GiN iuiee weg ethnic tnnk YN Wh 5 6 
Diapophysial caudals...........++++- 25 15 25 
Non-diapophysial caudals........--.. 45 " 55 
The zygapophyses in all three forms terminate at or near the 
end of the rib-bearing vertebra. In the cervical region they are 
strong, diminishing but little in size through the thoracic region. 
In the region which I call lumbodorsal, they become weaker. The 
vertebre increase in length through the thoracic region, but dimin- 
ish very rapidly in length at the end of the costiferous series. 
The length of C/dastes velox is about twelve feet, that of Plate- 
carpus corypheus nearly fourteen, while 7y/osaurus proriger, one of 
the smaller species of the genus, was over twenty-three feet. The 
smallest species of Clidastes, C. pumilus, if it be a distinct species, 
was about six feet in life. The largest species of the Kansas 
Mosasaurs, Zylosaurus dyspelor had a length of nearly thirty feet. 
Only one other species of the group larger than 7ylosaurus dyspelor 
has been described from America—Mosasaurus maximus Marsh, 
trom New Jersey. If it had the same proportions as Tylosaurus its 
length would be about thirty-two feet. If like C/dastes, as it was 
in all probability, its length would not exceed thirty-six feet. Eve 
ropean forms somewhat larger than this have been described, pos- 
sibly reaching a length of nearly forty feet. The text-books and 
popular descriptions place the length of these animals at from 
seventy-five to one hundred feet! 
The food of the Mosasaurs must have consisted chiefly of fishes 
of moderate size with occasional victims of their own kind. While 
the flexibility and loose union of the jaws undoubtedly permitted 
animals of considerable size to be swallowed, the structure of the 
thoracic girdle would not have permitted any such feats of degluti- 
tion as the Python and Boa are capable of. The animals must 
have been practically helpless on land. They were not sufficiently 
serpentine to move about without the aid of the limbs, and these 
were not at all fitted for land locomotion. They lived in the open 
sea, often remote from the shores. Their pugnacity is amply indi- 
cated by the many scars and injuries they received, probably from 
others of their own kind. 
