Merriam.] 



Triassic Ichth yopterygia . 



89 



gation will bring to light remains of Shastasaurus at numerous 

 points outside of the Paeifie Coast region of North America. 



DESCRIPTION OF SPECIES. 



Shastasaurus perrini. n. sp. 



Pes. 5, 6 and 7. 



The only specimen of this species known was discovered in 

 the Cove some years ago by a collecting party working under the 

 direction of Professor James Perrin Smith. Being too large to 

 to be handled without special appliances, it was left in the held 

 till the fall of 1901, when Professor Smith generously turned 

 it over to the University of California party then working in 

 the Cove. 



This specimen exhibits an unbroken series of eighty vertebra?, 

 beginning near the anterior end of the dorsal region and ending 

 well beyond the middle of the tail. The majority of the ribs 

 from the lower side of the body and a number from the upper 

 side lie next the vertebrae to which they were attached. The 

 whole of the posterior arch and the most important parts of the 

 hind limbs are present. Of the anterior girdle only a large 

 fragment is left. The head and anterior limbs were in a portion 

 of the slab which had been weathered or broken off. As yet 

 no trace of them has been discovered. 



This skeleton was found a considerable distance below the 

 top of the layer of shaly limestone of the Trachyeeras beds. As 

 may be seen in Plate 5, fig. 1, the slab upon which it lies is 

 largely made up of molluscan shells, among which Halolia 

 stiperha is the most common form. A large specimen of Tropifes 

 rests against the lower side of the tail. 



One of the most important characters of this species is found 

 in the form of the vertebral centra, which are much longer than 

 in the other known forms of the genus. In the second vertebra 

 the ratio of length to height is 1:1.83, in the twenty-fifth 

 1:1.33, and in the fifty-fifth 1:54. The later caudals rapidly 

 become shorter and higher. In the tenth vertebra of osmonti, 

 which is near the place of the second of the perrini specimen, 



