FOSSIL FISHES AND CEPHALOPODS. 
81 
belongs to a primitive section of the Theromorphs, or 
Anomodonts, which include the ancestors of Mammals. 
Of the galleries running northwards from the Fossil Eeptile 
gallery, the one nearest to the central hall is entirely devoted 
to the display of the enormous collection of Fossil Fishes. A 
great proportion of the oldest of these belong to groups now 
quite extinct. Perhaps the most remarkable of all, and cer- 
tainly those most unlike existing forms, are the armoured 
Devonian Fishes known as Cephalaspis, Pterichthys (fig. 54), 
&c. In the figure of the latter letters are placed on the various 
plates of armour, as well as on other parts of the body. The 
explanation of these will be found in the " Guide to Fossil 
Fishes." 
Fig. 52. — A Giant Pterodactyle (Pteranodon occidentalis) from the Cretaceous of 
Kansas. (Original span about 18 feet.) Compare the wing which is supported 
by the outermost finger with that of the Bat in Fig. 7. 
The next contains the Cephalopods, a group of Molluscs 
abounding in extinct species, of which the Belemnites, Turrilites 
(fig. 55), and Ammonites (fig. 56) are some of the best-known. 
The form and structure of their nearest living representatives, 
the various species of Cuttle-fishes, Squids, Argonauts, and 
Nautilus (fig. 30, page 54) are illustrated by models and 
drawings and specimens placed near the entrance of the gallery 
and along the top-line of the wall-cases. The third gallery Extinct 
contains the remaining Molluscs and Brachiopods ; the Echino- a^^piant?^^ 
derms, Worms, and Crustaceans ; the fourth, the Corals, Sponges, 
Protozoa, and Fossil Plants. In these last two galleries the 
British specimens are placed in the table-cases, and those of 
foreign origin in the cases round the walls. 
