FOSSIL VERTEBRATES — REPTILIA Wf WS 
only from fragments, are Chonchiosaurus, Simosaurus and Lampro- 
Saurus. 
Lariosaurus was very much smaller than Vothosaurus, being 
less than 3 feet in length. It is known from the Trias (Muschel- 
kalk) of Italy. The skull is triangular in outline and very much 
shorter than the skull of the first genus. The temporal fosse 
are large, the orbits and the nares small and lying quite close 
together. There were 20-21 cervical vertebrz, 24-26 dorsal, 
and about 30 caudals. There was in this genus, as in the former, 
a ventral armor of small abdominal ribs. 
Pachypleura, from the Trias of Italy, was very similar to 
Lariosaurus, but was even smaller. It was remarkable for the 
length of the tail which was nearly half as long as the body. 
There were about forty vertebre in the tail. The same genus is 
known from the Trias of Germany. 
Plesiosauride: large forms with the limbs developed as 
paddles. There were five digits on each foot, but the number of 
phalanges is much above the normal. The whole pectoral girdle 
reaches a very great development in these forms so that it forms 
a bony protection for the thoracic region. 
Plestosaurus.—The head of this genus was small and rather 
elongate, the temporal fosse were large and the orbits and nares 
small. The teeth were numerous in both jaws. They were 
long and slender, slightly recurved and set in deep alveoli. They 
were somewhat large at the anterior end of the snout. The 
neck in some of the species of the genus, was as long as the 
rest of the body. There were 20-72 cervical vertebre, 20-25 
dorsals, and 30-40 caudals. There was a system of abdominal 
ossicles consisting of a centerpiece and two or more smaller 
lateral pieces. The most characteristic part of the anatomy of 
the animal is the pectoral girdle. The coracoids became very 
large and the clavicles reduced to small proportions. The exten- 
sion of the coracoids of the two sides causes them to meet in 
the median line and they together join the clavicles and the inter- 
clavicle in front, making a thick bony cuirass covering the region. 
The pelvis does not show such a great expansion, but there is a 
