720 SLODIES HOR SRODENTS 
Platecarpus.—This form was of intermediate size, one genus 
reaching a length of about 14 feet. Cervicals, 7; precaudals, 
27-28; caudals about 80, probably somewhat less than in the 
Tylosaurine. From Kansas, Colorado, and Mississippi. 
Phoplatecarpus: from the Maestricht of Belgium. 
Taniwhasaurus: from the Cretaceous of New Zealand. 
Mosasaurine: hind feet tetradactyl; carpus and tarsus fully 
ossified and with not more than six phalanges in each digit; 
trunk rather long with a shorter tail; rostrum short. 
Mosasaurus: from Belgium, England, New Jersey, Dakota, 
Alabama, and North Carolina. Specimens from New Jersey 
show a length of 32-36 feet, and some of the European forms: 
were as long as 40 feet. 
Clidastes—This was one of the smallest of the genera. C. 
pumilus was only about 6 feet long, and no species was over 12— 
14. Cervicals, 7; precaudals, 42; and caudals, 70. From Kan- 
sas, Colorado, New Jersey, Mississippi, and Alabama. 
Many less well-known genera have been described from the 
rocks of this country and Europe, showing that the group had a 
considerable development while it lasted. 
Speaking of the group, Williston says: ‘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 deglutition as 
the Python and Boa are capable of. The animals must have been 
practically helpless on land. They were not sufficiently serpen- 
tine to move about without the aid of 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 their own kind.” 
PTEROSAURIA. 
_ The Prerosauria or Pterodactyls, as they are more popularly 
called, were reptiles that were adapted to a flying or soaring life 
