i 



K C. Case — Amphibian Fauna at Linton, Ohio. 135 



Odonterpeton 



(Estocephahis 



Pelion 



Phlegethontia 



Pleuroptyx 



Ptyonius 



Saurerpeton 



Saiiropleura 



St eg ops 



Thyrsidium 



Tuditanns 



If we examine the animals as described and illustrated in 

 Moodie's excellent monograph, we find that they were, one and 

 all, provided with sharp, conical teeth, suitable only for a car- 

 nivorous or an insectivorous diet. This eliminates the vegeta- 

 tion of the period from consideration as a possible source, at 

 least as an immediate source, of food, but introduces a most 

 effective element of stress in the competition between the ani- 

 mals themselves, on the one hand to capture prey and on the 

 other to escape the attack of predatory forms. 



The possible sources of food were the fishes, the amphibia, 

 and very probably the abundant arthropods, molluscs, and 

 insects, though practically no traces of invertebrates have been 

 found with the remains of the amphibians, except the casts of 

 spirorbis-like forms. While there can be little doubt that some 

 of the amphibians were carrion eaters and scavengers, the ulti- 

 mate food supply must have been the invertebrate fauna of the 

 waters and banks, and the very meagerness of the remains of 

 such a fauna speaks eloquently of the crowded habitat and the 

 eager search for every edible particle. Beyond this the diet 

 was of flesh and the fauna was self -devouring. 



From the description given it seems fairly certain that the 

 amphibian fauna was isolated in a pool of clear water sur- 

 rounded by a great stretch of swamp. The ordinary factors of 

 environment which influence the development of a fauna were 

 absent or ineffective, the physiography and the climate were 

 monotonous in the extreme ; the vegetation had only an indirect 

 effect. The main stress upon the life was competition within 

 the fauna. This stress became very high with the crowding of 

 the pool, but as the monotonous environment afforded but lim- 

 ited possibilities for the formation of new habits, adoption of 

 new habitats or the assumption of a new group of contacts in 

 any form, it was not relieved by any over-specialization either 

 in structure or habit. A study of the amphibia reveals only a 

 very normal group of animals. They varied in size from ten 

 feet to six inches in length, some were squat and sluggish, 

 others lithe and serpentiform, some even so snake-like that 



Am. Jour. Sci.— Fourth Series, Vol. XLIV, No. 260.— August, 1917. 

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