402 PALAEONTOLOGY 



regions. It is very similar to the Carboniferous fauna, 

 except that the Ammonoidea have far more complex 

 suture-lines, frequently with many-pointed lobes and 

 rounded saddles. 



In other areas an impoverished (inland sea) fauna is 

 found, consisting mainly of BRACHIOPODS and LAMELLI- 

 BRANCHS, and a terrestrial flora which is an impoverished 

 form of the Carboniferous flora. 



III. GENERAL FEATURES OF MESOZOIC 

 FAUNAS. 



CORALS are less abundant and of entirely new types. 



Cystids and Blastoids are extinct, CRINOIDS become 

 less and less common ; Echinids are abundant, and incliif'- 

 Irregular as well as Regular forms. 



Brachiopods are common, especially Terebratulids 

 and Rhynchonellids. 



Lamellibranchs are abundant, and Gastropods are 

 common. 



Ammonoidea are very abundant, except towards the 

 end of the era ; their sature-lines are extremely complex 

 as a rule. They serve as zone-fossils (pp. 384-390). 



Trilobites are quite extinct. 



VERTEBRATA: Fishes (sharks and Ganoids) and 

 Reptiles, both terrestrial and marine, are abundant. 

 MAMMALIA are exceedingly rare and small. 



LAND-PLANTS : principally Cycads, also CONIFERS and 

 FERNS. 



SPECIAL FEATURES OF THE SEPARATE SYSTEMS. 



7. TRIASSIC- As with the Permian, though to a 

 much less extent, the true marine fauna is restricted in 

 area, being preserved principally in the Alps and other 

 great mountain chains. 



ECHINOIDS are rare and of very special types. 



Brachiopoda : spire-bearing forms are still numerous, 

 as well as Terebratulids and Rhynchonellids, but nearly all 

 other Palaeozoic families are extinct, 



