FES SILOS IRON SIMGDIZIN IES 
Pistosauride: the skull, elongate and terminating in a sharp 
rostrum in front; the anterior nares, very small and formed by 
the maxillaries and the premaxillaries; the nasals, greatly 
reduced and taking no part in the nares; a single foramen in the 
palate at the anterior end, forming the posterior nares or choane. 
Fistosaurus is the single genus; from the Muschelkalk of 
France and Germany. 
PYTHONOMORPHA. 
The Pythonomorpha are specialized forms of the Lacertihan 
branch developed during Cretaceous time. They were sea-living 
lizards, corresponding in many particulars to the popular idea of 
the sea serpent. They were greatly elongated in form, the limbs 
were specialized as paddles, and the whole body adapted to an 
aquatic life. They resembled the living Varanus or Monitor. 
The head was long and flat; the eyes, small and located far 
back in the skull, were supplied with sclerotic plates. The 
major part of the skull was formed by the long jaws, which 
were furnished with sharp, conical teeth, straight or slightly 
curved backwards, and set in separate alveoli. The upper 
jaw was solid and strong, with or without a rostrum extend- 
ing in front of the teeth. The lower jaw was not united at 
the anterior end with the jaw of the opposite side, but was 
attached to it by cartilage, thus allowing a great degree of 
freedom in the action of the two jaws. Moreover, the jaw of 
each side was furnished with a second joint at about the middle, 
which allowed the jaw to be bent out or inward in a horizontal 
plane, and enabled the animal to swallow the large animals upon 
which it preyed. The brain cavity was small, and the quadrate 
bone was joined to the skull loosely, as in the snakes, allowing 
the jaws to be opened very widely. There were a great many 
vertebra, giving a great length to the neck and tail as well as to 
the dorsal region. The vertebre were furnished with very per- 
fect articular surfaces, concave in front and concave behind; 
besides the regular arrangement for the connection of the verte- 
bre there were accessory articular processes such as occur in the 
