38 
The armoured Stegosaurian Reptile, Hylaeosaurijs 
armatus , is shown by a cast of Mantell’s original specimen 
from the Weald of Sussex. 
Fig. 40. Restoration of a Stegosaurian Reptile — 
Stegosaurus ungulatus. 
Upper Jurassic. Colorado. 
A fine collection of Fish-lizards, or Ichthyosaurus, is 
hung on the wall of this Gallery, comprising five species 
(I. acutirostris , I. communis , I. intermedins, I. platyodon, 
and I. tenuirostris). Some of these are original examples, 
and most of them show the kinked caudal region of the 
vertebra which indicates the fish-like heterocercal tail, 
predicted by Owen and confirmed by later discoveries. 
Compare the Queensland specimen from the later formation 
of the Cretaceous (in Case on east wall of Gallery), representing 
the last dying members of the race which, besides living in 
European seas, sought refuge in southern waters, as in Chile, 
New Zealand, and Australia. 
Thaumatosaurus, a short-necked Marine Reptile, is 
represented by a fine replica of the fossil which is in the 
Museum of the Royal Dublin Society. It measures about 
27 feet in length. These Sauropterygians (“ Lizard-finned ” 
Reptiles) were contemporaneous with the Fish-lizards, and 
had similar paddles, but unlike them, the five reptilian toes 
were not supplemented by extra bones. (See Fig. 9.) 
A cast of Plesiosaurus hawkinsi here exhibited is another 
but more slender form of the same order. 
