VERTEBRATA. 



No. 95. [301] Sauropus primaevus, Lea. 



Tracks, on slab (cast). These reptilian foot-prints were discovered in 1849 

 in a formation of red shales (Mauch Chunk Red Shales), at the base of the 

 Coal Measures near Pottsville, Peun. The animal appears to have had five 

 toes on its fore feet and four toes on the hind pair. There being no trace of 



dragging of the feet, it 

 probably had longer 

 legs than the crocodile. 

 A groove-like impres- 

 sion was left by a slen- 

 der tail. The stride, 

 from toe to toe, meas- 

 ures thirteen inches ; 

 and the tracks are three 

 and one-half inches 

 long. The hind-feet 

 stepping upon nearly 

 the same spot as the 

 fore-feet partially obliterated the first impression. The original is in the pri- 

 vate collection of the late Isaac Lea of Philadelphia, by whom it was dis- 

 covered and described. Size, 36 x 17. 



No. 96. [291] Archegosaurus Decheni, Goldf. 



Head and Part 

 OF Trunk (cast). 

 This species dis- 

 putes with the Sau- 

 ropus of Lea and 

 the Dendrerpeton 

 of Dawson for the 

 honor of being the 

 first of air-breath- 

 ers. It seems to 



have had permanent gills and persistent notocliord, paddles instead of legs, 

 and to have been adapted for an aquatic life. Goldf uss considered it a Sau- 

 rian; Agassiz claimed that even in its limbs — its most reptilian feature — it is 

 closely like Ganoid fishes of the genus Polyj)terus ; while the majority of 

 naturalists regard it as a proteoid Labyrinthodont. It had sculptured bony 

 plates on the head and bony scales on the body, like Ganoid fishes; and the 

 greater part of the skeleton retained its cartilage. The skull is depressed and 

 triangular, and the lower jaw differs from that of fishes' in the great length of 

 the angular pieces, but resembles it in simplicity. The teeth are conical and 

 of labyrinthic structure, and implanted in sockets. Apparently it was a gen- 

 eralized form, connecting the amphibians and the sauroid fishes. Prof. Owen 

 places it in a distinct order, the Oanocepliala. This specimen was discovered 

 in the coal-field of Saarbruck, Rhenish Prussia, and is in the Ward Collection 

 of the University of Rochester. Size, 13 x 5. 



