EEPTILIA. 53 



No. 196. Polemarchus gigas, Hk. 



Track, on slab. This animal, a Lizard according to Hitchcock, has given no 

 evidence of having had more than two feet. These are plantigrade, or even calci- 

 grade, the heel sinking deeper than the toes. There are three long, slender toes, 

 directed forward, and a fourth, like a spur, turned inward. The length of the 

 foot is 14.8 inches, and the width of the heel, 3.9 inches. This print was found at 

 Chicopee Falls, Mass., in the Lias (?) sandstone, and belongs to Amherst College. 



Size, 19 x 11. Price, $2.75. 



No. 197. Plectropterna minitans, Hk. 



Track, on slab. This animal was probably quadrupedal and lacertilian. 

 This specimen is the track of a hind-foot, which bears four slender toes, three 

 directed forward. It was found in the Lias (?) of Wethersfield, Conn., and is in 

 the Museum of Amherst College. Size, 4x7. Price, $1.00. 



No. 198. Plectropterna . Hk. 



Track, on slab. From the same locality and Museum. 



Size, 4x7. Price, $1.00. 



No. 199. Argozoiim , Hk. 



Track, on slab. . This " narrow-toed Bird" was tridactyle, the toes being 

 curved, and digitigrade. The print was found in the Lias (?) of Chicopee Falls, 

 Mass., and is in the Museum of Amherst College. Size, 11 x 7. Price, $1.50. 



CLASS III — EEPTILIA, 



The history of fossil Reptiles exhibits a degradation in type. The 

 genera first created were of the most highly organized types; while 

 those which maintain a persistent form of some of the embryonic stages 

 do not appear until the Tertiary Period. Reptilian life culminated 

 during the deposition of the "Wealden. The first osseous remains are 

 those of the Carboniferous Archegosaurus. (The Stagnolepis, formerly 

 ranged by Agassiz among the Fishes, but decided by Huxley to be a 

 Crocodilian, the Telerpeton and Hyperodapedon found at Elgin, are now 

 considered Triassic, instead of Devonian.) All the species of that 

 Period were Amphibian. If the Labyrinthodonts (as Owen thinks) 

 are Saurians arrested in their development on the level of the Batrach- 

 ians, we then have proof that representatives of a permanent larvae con- 

 dition existed among the loricated Reptiles of the ancient world, in like 

 manner as the Sirens do among the recent Batrachians. 



