346 THE BOOK OF THE ANIMAL KINGDOM 



no trace of itself. We know from fossils that have been identified 

 that there were large Scorpions and Spiders as well as Dragon-Flies. 

 Beetles were in evidence, Cockroaches and Walking-Stick Insects. 

 The plants produced spores, but no seeds; they bore no flowers 

 in the ordinary sense of the term, and so provided no nectar for 

 bees, wasps and honey-feeding insects. The ancient Trilobites were 

 becoming rare, and among the shell-animals the lower molluscs, 

 known as Brachiopods, were giving way to more fully developed 

 Lamellibranchs, bivalves like the Oyster, Cockle and Mussel; and 

 to the Gasteropods, which are univalves, and of which our modern 

 Snails may be taken as types. There were Fishes in the Carbon- 

 iferous waters, chiefly Ganoids, especially in the lagoons. Sharks 

 existed and preyed upon smaller fry. 



In such an environment the earlier Amphibia known as Laby- 

 rinthodonts, to which some reference has already been made, were 

 the probable monarchs. They are certainly the most highly- 

 developed animals of which the Carboniferous rocks yield remains. 

 They may be likened to our modern Newts and Salamanders. 

 Several kinds have been found varying in size from an inch or two to 

 seven or eight feet ; the larger ones were the lagoon monsters. It has 

 been surmised that the amphibian known as Archegosaurus was 

 among the first of the vertebrate air-breathers; its remains suggest 

 a likeness to the Mud-fish, which in the wet season lives in water, but 

 in dry times buries itself in mud and breathes by the agency of an 

 air-sac, which is a primitive lung. Some of the Carboniferous 

 amphibians dispensed with legs, although the majority possessed 

 them ; their tails were well developed and strong, enabling them to 

 swim with a powerful movement. 



The amphibians reached the height of their development in the 

 Permian period, when many new forms appeared. It is in Permian 

 strata that remains of true Reptiles are found, and they indicate 

 a marked forward movement in the development of life-forms. But 

 it is in the Secondary strata that they reach their finest growth. 

 The Ichthyosaurs (Fish Reptiles) attained large dimensions. The 

 head of one possessed by the Geological Society, and preserved in 

 its rooms in London, is some five and a half feet long, and the animals 

 must often have been upwards of forty feet from tail to snout. They 

 had thick bodies, and possessed a pair of big paddles to the fore 

 and a smaller pair behind. Their tails were fishlike. They could 

 swim easily in the sea, which was their favourite element, but on 



