512 ZOOLOGY. 
The Ichthyosaurs were colossal reptiles from two to thirteen 
metres (six to forty feet) in length, swimming in the ocean by 
four paddle-like limbs consisting of six rows of digital bones 
Fig. 448.—Skull of Ichthyosaurus ; lateral view. Pma, premaxillary bone ; Ma, 
maxillary; W, nasal; Fr, frontal; Pr, prefrontal; Pof, postfrontal ; Pa, parietal 
JZ, lachrymal; M, malar; Qj, quadratojugal; Q, quadrate ; Pob, postorbital ; S¢ 
equamosal; D, dentary; Ang, angular; Art, articular; 9. Ar, subarticular ; Per 
pterygoid.—After Cope. 
the head was very large, the neck very short, and the orbits 
were enormous; the vertebrae were remarkably short and bi- 
& concave. They were carniv- 
.88 & orous, and powerful swim- 
8a mers, and common in the Ju- 
rassic seas of Europe; one 
form existed in the Jurassic 
times in Wyoming. 
Order %. Theromorpha.— 
This order is divided into the 
Pelycosauria and Anomo- 
dontia. ‘The beaked Saurians 
were somewhat lizard-like, but 
Fig. 449.—Posterior view of the skull of were synthetic types, combin- 
Ichthyosaurus; lettering as in Fig. 443, . 
with following additions ; Bo, panleeeis ing the characters of the Ich- 
Pecimaen t o, opithotic 3 Sap eatne thyosaurs, the turtles, the 
stapedial or hyomandibular.—A iter Cope. 8 oh enod On, with those of liz- 
ards, Dinosaurians, and crocodiles. The skull was short, 
and in Dicynodon the jaws in front had the nipping, horny 
beak of a turtle, while from behind in the upper jaw pro- 
truded two long, curved, canine teeth. Dicynodon tigriceps 
Owen, had a skull about half a metre (20 inches) long, 
