August 14, 1890] 



NATURE 



373 



skull is deeply channelled on its surface, as in the 

 Crocodilia and the Labyrinthodontia. 



From the flattened wearing away of the crowns of the 

 teeth, Prof. Owen has suggested it was a vegetable- 

 feeding reptile. The vertebrae of Pariasaurus are noto- 

 chordal, frequently having intercentra present, and there 

 are not more than two vertebrae united to form the 

 sa<^um. 



The Permian rocks of Texas have yielded to Prof 

 Cope a most remarkable genus of Anomodont reptiles, 

 named by its describer Empedias molaris. The dentition 

 forms an uninterrupted series without a distinct tusk, the 

 incisors differing but little from the cheek-teeth in form, 

 each tooth having a more or less distinct transverse 

 edge. The teeth are about fifty-six in number. 



The genus Naosaunis, also from the Trias of Texas, 

 makes us acquainted with a very curious reptile, in which 

 the neural spines of the vertebras are of most enormous 

 height, and each spine has often as many as six paired 

 horizontal processes at intervals produced from its sides. 



Fig. 6.— Anterior view of a dorsal vertebra oi Naosaurus claviger. Cope ; 

 from the Permian of Texas. (J nat. size.) Ce, centrum. 



This reptile when living must have had an enormous 

 dorsal crest, like some monstrous newt, rising from its 

 back, but it is difficult to conceive any advantage which 

 its owner could possibly derive from such an unwieldy 

 appendage. 



Turning to the Amphibia, one cannot fail to be struck 

 by the similarity in the form of the cranium, and its 

 external ornamentation, in the Labyrinthodontia and the 

 Crocodilia. The body is also long, usually lacertiform, 

 and the feet pentadactyle ; a bony thoracic buckler and 

 bony scutes are frequently present on the ventral aspect 

 of the body. Doubtless these old Triassic reptiles were 

 ancestrally related to the later Crocodilia, as well as to 

 other and higher forms of Vertebrata. 



Teeth iji the Labyrinthodonts are usually present on 

 the palatines and vomers, and more rarely on the ptery- 

 goids ; and there is very generally an ossified sclerotic 

 ring to the orbit. The vertebrae exhibit considerable 

 variation in condition, being amphicoelous, and fully 

 ossified in some instances, or with a notochordal canal, 



NO. IOvS5, VOL. 42] 



or with large intercentra and the centra represented by 

 paired lateral pieces (pleurocentra) in others. 



The parietal foramen is always present in the cranium, 

 and in the Mastodonsauridas the occipital condyles are 

 well ossified. 



The Trias of Wiirtemberg has yielded the finest known 

 examples of these Labyrinthodont reptiles, quite re- 

 cently described and figured by Dr. Fraas ; but the most 

 complete skeletal remains of Amphibia have been ob- 

 tained from the Gaskohle (Lower Permian) of Bohemia 

 by Dr. Anton Fritsch, of Prague ; others from Germany 

 by Prof. Credner, of Leipzig ; and by Prof Gaudry from 

 the Lower Permian of Autun. The best examples in the 

 collection are those of Archagosaurus from the Lower 

 Permian of Saarbriicken, and of Loxomma from the 

 Coal-measures of Coalbrookdale and Scotland. 



To the Ecaudata (frogs and toads) little interest 

 attaches in a palasontological sense, as no tailless forms 

 of Amphibia are known earlier than the Miocene period ; 

 but good examples of these have been obtained from the 

 Brown-Coal of Rott, near Bonn, and from the Fresh-water 

 Tertiary Limestone of Oeningen, which also yields the re- 

 mains of Cryptobranchus scheuchzeri, closely related to the 

 giant salamander now living in the fresh-waters of Japan. 



Contrasting for a moment the Mammalia with the 

 Reptilia, while many genera of the former, such as 

 Dinotlieriujn, Mastodon, Machairodus, Phenacodus, 

 PalcBotherium, Anthracotheriutn, Taxodon, Sivatherium, 

 Dinoceras, and others, have died out, eight entire orders 

 of Reptilia and Amphibia, embracing more than 200 

 genera, have all disappeared. This is the more readily 

 understood when we consider the comparative periods 

 of geological time during which the Mammalia and 

 Reptilia have respectively flourished ; for whilst it is true 

 that the earliest known forms of Mammalia made their 

 appearance as far back as the termination of the Triassic 

 period, yet during the whole of the succeeding Jurassic 

 and Cretaceous periods their numbers were few and their 

 forms quite insignificant ; and it is not until we arrive at 

 Eocene times that the Mammalia commence to occupy 

 anything like a prominent position in the animal 

 kingdom. On the other hand, the Amphibia began to 

 be abundant as early as the Coal period ; and the Reptilia 

 (ushered in by Proterosaurus) in the Permian attained a 

 maximum development both in size and numbers in the 

 Lias and Oolites, whilst the Mammalia were yet only in 

 the incipient stage of their development. 



Great credit is due to Mr. Lydekker for the manner in 

 which he has performed the task of preparing these Cata- 

 logues for the National Collection, a work which will 

 doubtless prove of extreme value to students of com- 

 parative anatomy and to workers at a distance who desire 

 to know what objects in any particular family or genus 

 the Museum possesses. 



We could wish that greater distinctness had been given 

 in printing these Catalogues to the important fact of par- 

 ticular specimens being the ones which are known as 

 "types," and which are the actual ones that have been 

 figured and described ; where this is mentioned it does 

 not catch the eye at once, as it should do. We would 

 advocate the placing of such information in a separate line ; 

 and, if possible, they should be marked prominently by the 

 use of special type. Perhaps the word " type " or " figd." 

 could be inserted in black letter and begin a separate line. 



Again, the formation and locality are hardly prominent 

 enough, and under each genus we would like to see the 

 " range in time " and also the "geographical distribution " 

 given as a separate paragraph. 



We hope this series of Catalogues, so helpful to all real 

 workers, may be continued and completed for every 

 group in the Geological Department. The Trustees could 

 not perform a more useful service to science than by 

 urging forward the issue of these works in every 

 Department of the Museum. 



