O. C. Marsh — Notes on Triassic Dinosauriat, 545 



On Plate XYI, figure 4, is shown the hind foot, also one- 

 fourth natural size, of Ammosaurus, a genus nearly allied to 

 Anehisaurus. In this foot, the tarsus is much more complete. 

 The astragalus has a slight ascending process, the calcaneum 

 is closely applied to the end of the fibula, and there are three 

 well-developed bones in the second row. The fifth digit had 

 only a single phalanx. The sacrum and ilia of the type 

 species of Ammosaurus are shown on Plate XVII, figure 3. 



Anchisaurus solus, sp. nov. 



A fortunate discovery has recently brought to light almost 

 the entire skeleton of a diminutive Dinosaur, which may be 

 referred to Anchisaurus, but clearly belongs to a distinct 

 species. It was found in nearly the same horizon as the 

 remains above described, and in the immediate vicinity, so 

 there can be little doubt that it was a contemporary. The 

 skeleton is imbedded in a very coarse matrix, so difficult to 

 remove that the investigation is only in part completed. The 

 portions uncovered show the animal to have been about three 

 feet in length, and of very delicate proportions. The bones 

 of the skeleton are almost all extremely light and hollow, but 

 most of them are in fair preservation. 



The skull, so far as it can now be observed, resembles the 

 one just described. The teeth are numerous, and inclined 

 forward. The orbit is very large. The quadrate is inclined 

 forward, and the lower jaw is robust. The entire skull is 

 about 65 mm in length, and the lower jaws the same. 



The neck was very long and slender, the first five cervicals 

 measuring S0 mm in extent. The dorsals are also elongated, 

 the last six covering a space of 135 mm . The number of verte- 

 brae in the sacrum cannot yet be determined. The caudal 

 vertebrae are short, the first ten occupying a space of 140 mm . 



The humerus has a very large radial crest, and is 66 mm in 

 length. The rest of the fore limb, so far as made out, is 

 similar to those in the species described. The tibia is about 

 ggmm m i en gth. There were five digits in the hind foot, but 

 the fifth is represented only by the rudimentary metatarsal. 

 The animal when alive was about as large as a small fox. 



The European Triassic Dinosaurs with which the above 

 American forms may be compared are mainly represented by 

 the two genera Thecodontosaurus, Riley and Stutchbury, 

 from the upper Trias, or Rhtetic, near Bristol, in England, 

 and Plateosaurus (Zanclodon), von Meyer, from nearly the 

 same horizon, in Germany. The writer has investigated with 

 some care the type specimens, and nearly all the other known 

 remains of these genera found at these localities. 



