INTRODUCTION. xxv 



several genera appeared for the first time during the early part of this period ; but 

 there is nothing to indicate any great phytological break between the two widely- 

 separated systems — the Carboniferous and Triassic. If it be correct, as stated, that 

 Cycadeous Gymnosperms occur in the Coal-measures of Bohemia, and a species of 

 Teeniopteris {T. Echhardti) in the Mansfeld Kupfer-schiefer, it will follow, that the 

 Deuterozoic period is not so much distinguished from the Protozoic by any peculiarity 

 of its great phytological groups. Generically these periods are related to each other : 

 they are also, to a certain extent, specifically connected : it may, therefore, be fairly 

 concluded, that the Permian Flora did not differ to any material extent from either the 

 Carboniferous, or the Triassic. 



Of the animal sub-kingdom Badiata, little can be predicated. The Polyparians of 

 the Triassic rocks are confessedly too little known to be referred to. The Echino- 

 derms are in the same category. Cyathocrinus ramosus, Archceocidaris Verneuiliana, 

 and the Corals, however, give the Permian Radiata a Carboniferous aspect. 



Referring to the class Crustacea, the abundance of Trilobites in the Carboniferous 

 rocks forms a striking contrast to their marked absence in the Permian, and all 

 subsequent formations : in this point of view, the Permian system possesses a negative 

 deuterozoic aspect ; while Kutorga's Limulus oculatus gives it a positive secondary 

 organic facies : the connexion, however, between the Permian, and Carboniferous 

 systems is still maintained by means of the Coal-brook Dale Xiphosurians. 



The Molluscous sub-kingdom binds together the Carboniferous, Permian, and 

 Triassic systems. Several species of the Carboniferous period continued to live, or 

 were closely represented, in the Permian ; and a few appear to have had their 

 existence prolonged into the Triassic. There is a strong generic and a faint specific 

 relation running through the three systems ; but taking all the classes into consideration, 

 especially the Palliobranchiate, the relation has obviously more of a Protozoic than a 

 Deuterozoic character. 



As already observed, it is doubtful whether any of the Permian fishes have been 

 found in the Carboniferous rocks : apparently, then, the Permian system is specifically 

 distinct from the Carboniferous in its Ichthyan relations : generically they are 

 connected with "each other ; and in this respect the connexion is a very close one. 

 This cannot be so confidently asserted of the Permian, and Triassic systems ; though 

 the occurrence of heterocercal Goniolepidots in the Trias rocks near Coburg, — Sir 

 Phillip Egerton's fortunate discovery of the Pycnodont characters of Flatysomus, — 

 and the presence of the homocerque Tetragonolepis Murchisoni in the Permian rocks 

 of Russia, — approximate the fishes of the two systems more closely than was admitted 

 a few years since. 



We cannot as yet form any satisfactory conclusion — as to whether the Permian system 

 is more related to the Carboniferous than to the Triassic, in its reptilian fauna. The 

 occurrence of Labyrinthodons and Rhynchosaurs in the Triassic rocks, and, according to 



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