EEPTILIA. 



77 



No. 291. Archegosaurus Decheni, Goidf. 



Head, on slab. This "primeval 

 lizard" disputes with the Sauropus of 

 Lea for the honor of being the first of 

 air-breathers. Goldfuss considered it a 

 Saurian ; Agassiz claims that even in 

 its limbs — its most Keptilian feature — 

 it is closely like Ganoid fishes of the 

 genus Polypterus; while the majority 

 of naturalists regard it as a Proteoid 

 Salamandrian. It had sculptured bony 

 plates on the head like Ganoid fishes ; and the greater part of the skeleton retain- 

 ed 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. This specimen was discovered in the coal-field of Saarbriick, Rhenish 

 Prussia, and is in the Cabinet of the Natural History Society at Bonn. 



Size, 8x5. Price, -$2.00. 



No. 292. Labyrinthodon (Mastodonsaurus) Jaegeri, Owen. 



Head. This is the largest known Batrachian 

 having labyrinthic teeth, i. e. a convergence of nu- 

 merous inflected folds of the external layer of 

 cement towards the pulp-cavity. The form of the 

 animal was something between the Toad and Land- 

 Salamander. The body, estimated at nine feet in 

 length, was covered with scales. The head was 

 triangular ; the nostrils very small ; and the orbits 

 situated nearly halfway between the fore and back 

 part of the skull. In this specimen the skidl and 

 lower jaw are firmly closed. It was found in the 

 Upper Trias (Keuper) near Stuttgardt, Wirtem- 

 berg, and is in the Museum of that city. 



Size, 2 ft, 6 in. x 2 ft. 



Price, $8.00. 



No. 293. Labyrinthodon (Mastodonsaurus) robustus, Meyer. 



Head. This species differs from the L. Jageri chiefly in having smaller orbi- 

 tal cavities. It is the Capitosauras of Miinster. This beautiful specimen is in 

 two pieces, one showing both the upper and lower teeth in place, the other exhib- 

 iting the cranial plates. It is from the same locality and Museum as the preced- 

 ing. Size of the head, 24 x 16 ; of the armor, 25 x 14. Price of both, $10.00. 



