Pant IIL Sxov. ii. § 1] JURASSIC. i 
in the Yorkshire Lias and the Stonesfield Slate, was a true carni- 
vorous crocodile, measuring about 18 feet in length, and is judged 
by Phillips to have been in the habit of venturing more freely to 
sea than the gavial of the Ganges or the crocodile of the Nile. 
Of the long extinct reptilian types one of the most remarkable 
was that of the enaliosaurs or sea-lizards. One of these, the Ichthy- 

Fic. 371.—Lower Oouitic LAMELLIBRANCHS. 
a, Nucula Hammeri (Defr.); 6, Trigonia navis (Lam.) (3); c, Mytilus sowerbyanus 
(D’Orb.) (3). 
osaurus (Fig. 377, a), was a creature with a fish-like body, two pairs 
of strong swimming paddles, probably a vertical tail-fin, and a head 
joined to the body without any distinct neck, but furnished with 
two large eyes, having a ring of bony plates round the eyeball, 
and with teeth that had no distinct sockets. Some of the skele- 

Fic. 372.—Mippie Ooxriric LAMELLIBRANCHS. 
a, Ostrea hastellata (Schloth.) (3); b, Trigonia clavellata (Sby.) (4). 
tons of this creature exceed 24 feet in length. Contemporaneous 
with it was the Plesiosaurus (Fig. 377, b), distinguished by its long 
neck, the larger size of its paddles, the smaller size of its head, and 
the insertion of its teeth in special sockets, as in the higher saurians. 
These creatures seem to have haunted the shallow seas of the Liassic 
time, and, varying in species with the ages, to have survived till 
