List of Casts, Models, atid Photographs. 



35 



24. Hypohippus equinus {Scott) . 

 Middle Miocene, Pawnee Buttes, Colorado. 

 This three-toed Horse is not in the direct line of descent 

 of the modern horses, but on a somewhat conservative side- 

 branch. The skeleton is as large as that of a Shetland pony 

 and is mounted in full relief in a walking pose. The head, 

 limbs, and feet are in exceptionally fine preservation. The 

 side view shows best the general proportions of the animal; 

 the view from behind, which best displays the small lateral 

 digits, can also be supplied. Hypohippus is closely related to 

 Anchitherium of the Lower Miocene, from which it is probably 

 directly descended. This skeleton was found by Mr. Brown 

 of the American Museum Expedition of 1901. 



25. Ichthyosaurus quadriscissus Quenstedt. 



Jurassic Period, Holzmaden, Wurttemberg. 



This fine skeleton was presented to the American Museum 

 by the Royal Natural History Museum of Stuttgart, through 

 Prof. Eberhardt Fraas. It is of especial interest as showing 

 that the Ichthyosaurs were viviparous instead of egg-laying 

 reptiles. The skeletons of seven young (unborn) Ichthyosaurs 

 can be seen, partly in, partly washed out of the body-cavity. 



26. Portheus molossus Cope. 

 Upper Cretaceous (Niobrara) of Kansas. Found by C. H. Sternberg. 



This great fish is characteristic of the marine Upper Creta- 

 ceous chalk formation of Western Kansas. It was related 

 to the modern Tarpon of Florida but of gigantic size, this 

 skeleton being 18 feet in length. The head and tail are 

 especially fine; the ribs and fins are mostly restored in plas- 

 ter. It is much flattened and is mounted in low relief. 



27. Hippopotamus liberiensis Morton. 



The Pigmy Hippopotamus of the West Coast of Africa is a 

 rare species, almost extinct. This skeleton is semi-fossil, and 

 was presented by the Museum of Christiania, Norway. 



