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THE AMERICAN NATURALIST [Vol. XLIX 



the origin of reptiles from fishes through the Amphibia. 



We owe to Doctor Fraas of Stuttgart many important 

 contributions to the knowledge of the early air-breathing 

 vertebrates and he has recently (6) issued another memoir 

 on the labyrinthodonts of the Trias, the first study of 

 these animals since the appearance of his large memoir in 

 1889. 4 The present contribution is devoted to discussions 

 of new species and new facts concerning previously de- 

 scribed species. The Plagiostenntm granulosum is found 

 to be the most peculiar labyrinthodont yet described, in 

 that it is extremely frog-like in appearance, especially in 

 the huge size of the orbits and the expanded occiput. It 

 is interesting, furthermore, in the apparent absence or 

 indistinct preservation of the lateral line canals. The 

 photograph (Plate XVI, Fig. 1) of the dorsum shows 

 portions of the supra- and infraorbital canals. The re- 

 mainder of the cephalic system of sense organs was prob- 

 ably contained in pits, which, in the fossilized skull, are 

 not to be distinguished from the ornamental scrobicula- 

 tions of the membrane bones of the face. The auditory 

 meatus is on the posterior edge of the skull and is quite 

 large for the size of the skull. Doctor Fraas has given in 

 a drawing (Plate XVI, Fig. 3) the complete osteology of 

 the occiput of this unusual labyrinthodont. The re- 

 mainder of the memoir is devoted to a discussion of new 

 or disputed points in the osteology of various genera and 

 species of Triassic labyrinthodonts. 



Gregory (7) has reviewed the studies which have thrown 

 light on the crossopterygian ancestry of the Amphibia, 

 dealing especially with Watson's (11) recent paper on the 

 Larger Coal Measures Amphibia, and giving a list of thir- 

 teen contributions which deal directly with this derivation 

 of the Amphibia. 



Huene (8) has again described the mandible of the pe- 

 culiar Permian genus Diplocauliis although it has been 

 many times studied, described and figured. He states, in 

 his introductory paragraph : 



(iattuniren. wie I Mccratosaurus. EoserpHuti. Stou-ops. Ampliibanuii?, 

 *"Paleontographica," Bd. XXXVI. 



