TRIMERORHACHIS, A PERMIAN AMPHIBIAN 



251 



Notwithstanding the abundant but disconnected material, I 

 have been frustrated in the attempt to make out the complete 

 anatomy of Trimerorhachis, and it will only be by the fortunate 

 discovery of a connected skeleton that the tail, ribs, and feet will 

 be made known. The figures of the skull herewith given are based 

 chiefly upon three specimens. The most perfect of these, so far as 

 form is concerned, is a solitary skull and clavicular girdle found by 

 Mr. Miller in the same horizon as, and in the immediate vicinity 



Fig. 4. — Clavicular girdle of T. insignis, from below; four-fifths natural size 



of, the skeleton of Seymouria described by me in a previous paper. 

 The specimen originally was perfect and undistorted, but weather- 

 ing had carried away much of the thin roof, leaving the cast very 

 smooth and complete. These parts have been completed from 

 two other specimens of identical size and character, specimens 

 collected in Texas nearly twenty years ago by Professor Case. 

 The sutures separating the elements have been determined chiefly 

 from these three specimens, aided by parts of several others, and 

 I think can be relied upon. In their general courses and relations 

 there is but Httle novelty in the figures. All of them, except the 



