608 PIKJCEEDIXas OF THE XATIOXAL MUSEUM. vol. xxx. 



the eyes of the IchthA'osaurs. The teeth are small, few in number 

 and vevy sharp. All of the American forms are supposed to be 

 edentulous. 



The renuiins ot these reptiles oct-ur in P^urope and North America 

 in rocks of Jurassic and Cretaceous age. Pteranodon and allied forms 

 are particuhirly ai)undent in the Niobrara chalk of Kansas. 



<9 



Inches. 



Length of skull 



Length of tail 



Length of fifth digit 



Estimated expanse of wings 



SKULL OF TRICERATOPS CALICORNIS Marsh. 



In the series of Ceratopsia remains preserved in the National 

 Museum is a considerable part of a skeleton, the type of Ti-'treTatops 

 nilirorxix (No. -1:!>2.'^)." This species was descri})ed'' by Prof. O. C. 

 ^larsh just prior to the removal of that part of the fossil ^erteltrate 

 collection belonging- to the U. S. (leological Survey from New Haven to 

 Washington, and was l)ased upon cei'tain peculiarities observed in the 

 nasal horn-core. 



Plate XXXII shows the skull and prcdeutary of this animal as it is 

 Tiow exhibited. This specimen Sk. 2t»'' '2171/' was collected by the late 

 Mr. J. B. Hatcher from the Cretaceous (Laramie), on Lance Creek, 

 Converse County, Wyoming, in 1S!>1. 



With the exception of the left })arietal (of which only a small por- 

 tion remains) this side of the skull is very complete. The frill and 

 jugal region of the opposite side ai"e wanting. The other ])arts of the 

 skeleton preserved are a portion of tlu' atlas, 11 presacral \ertebra', 

 part of the sacrum, portions of both ilia, 2 pubes, (juite complete, 

 several cervical and thoracic I'ibs, and numerous fragments of the 

 skull and otlitn* l)ody elements, including many short pieces of the 

 ossilied tendons, so connnon along the backbone of Trachodon. In 

 cleaning the sacrum of No. i!>28 ossified tendons were found embt>dded 

 in the mati'ix. situated, as they must hav(^ been in life, in the nmst-l(\s 

 along the back on either side of the spinous processes of the vertel)ra\ 

 This is the tirst time these tendons have been found so far postericuly 

 in a member of the Ceratopsia. although their presence there had been 

 suspected. 



« Catalogue number of the V . P. National Museum. 

 '' Amerifau Journal of Science, (4), VI, p. 92. 

 'Ilatoher'n ori<rinal liclil number. 

 '' Marsh';^ number. 



