VERTEBRATE PALEONTOLOGY IN 1912 17 



Dr. C. W. Andrews for a plesiosaur from the Oxford Clay of 

 Peterborough. 



The lower jaw of a gigantic ichthyosaur discovered in the 

 Trias of Aust Cliff in 1877 and preserved in the museum at 

 Bristol is discussed by Prof, von Huene in Centralbl. fur Mm. 

 Geol. it. Pal. 1912, pp. 61-3, by whom it is considered to be 

 related to Mixosaurus and Merriamia. 



At the conclusion of a memoir on the structure of the skull 

 of that very remarkable Triassic reptile Placodus, whose bean- 

 like teeth seem evidently adapted for crushing the shells of 

 molluscs or crustaceans, Mr. F. Broili (Palceontographica, 

 vol. lix. pp. 147-55) remarks that the skull-roof possesses no 

 sign of those bony ridges and rugosities seen on the skull of 

 Placochelys but is, on the contrary, entirely smooth. From this 

 it is inferred that Placodus probably did not possess a bony 

 carapace, as such a structure was very likely associated with 

 a roughened skull ; this being confirmed by the absence of 

 direct evidence that bony plates have been found in association 

 with the skeleton. On the other hand, there may have been 

 a horny plastron. The alleged relationship to Placochelys is 

 therefore not borne out by the available evidence. 



Passing to the mammal-like groups of early reptiles 

 reference may be made first to an article by Prof. S. W. 

 Wilhston {Amer. Journ. Set. vol. xxxiv. pp. 457-68) on the 

 restoration of the cotylosaurian genus Limnoscelis, from the 

 Permo-Carboniferous of New Mexico. To repeat the author's 

 summary of the osteological characters of the genus would be 

 out of place and it must suffice to mention that this primitive 

 reptile, which attained a length of about seven feet and had 

 remarkably short limbs, probably frequented the borders of 

 swamps and marshes. 



To the Journal of Morphology for 1912 the same writer 

 contributes an account of the Cotylosauria, the group to which 

 Limnoscelis belongs. In a third communication, published in 

 the Journal of Geology for 191 1 (vol. xix. pp. 233-7), 

 Dr. Wilhston gives a restoration of Seymouria, a relative of 

 Limnoscelis, although regarded as typifying a family by itself. 

 It may be added that much interesting information with regard 

 to these and kindred forms may be found in an article by the 

 same palaeontologist in the Journal of Morphology, vol. xxiii. 

 PP- 6 37-66, on primitive reptiles in general. 

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