FOSSIL FISHES AND OEPHALOPODS. 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 Ptbeodacttle (_Pteranodon occidenlalis) feom the Cretaceous of 



Kansas. (Origioal 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-Une of the wall-cases. The third gallery Extinct 

 contains the remaining Molluscs and Brachiopods ; the Echino- invertebrates 

 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, 



G 



