22 KANSAS UNIVERSITY QUARTERLY. 



pre-sacral vertebrae. The vertebrae of these animals that have been 

 so designated by writers are in reality basal caudal. A distinctive 

 term for them — those with transverse, non-costiferous processes and 

 without chevrons — is needed, and we propose, provisionally, the term 

 pygial. There are seven in the present series, all characterized by 

 elongated transverse processes, and not differing much from each 

 other. The vertebrae lie in the matrix with the ventral aspect upper- 

 most, concealing the spine and upper parts. The under surface is 

 somewhat flattened, and, as in the preceding vertebrae, is gently 

 concave antero-posteriorly. The transverse processes are elongate, 

 stout towards the base, apparently all of nearly equal length, and 

 directed gently backwards and downwards. In the anterior vertebrae 

 the processes spring from near the front part : as the centra become 

 shorter they arise from near the middle. In the last one of the series 

 there are minute indications of chevrons. 



MEASUREMENTS OF THE PYGIAL CAUDAL VERTEBRAE. 



1. Length to rim of ball 36 millim. 



Width of ball 25 



Expanse of transverse processes 130 



Width of transverse process near base 17 



2. Length to rim of ball 33 



3. Length to rim of ball 31 



4. Length to rim of ball 29 



5. Length to rim of ball 28 



6. Length to rim of ball 27 



Expanse of transverse processes 130 



Width of ball 24 



7. Length to rim of ball 27 



The centra of those caudal vertebrae which have chevrons do not 

 differ much in shape. They become less constricted, and, back of 

 the middle of the series, are smoothly cylindrical in shape. The 

 transverse processes decrease gradually in length, disappearing en- 

 tirely in the twenty-fifth or twenty-sixth. The spinous processes are 

 more or less incompletely preserved in the anterior vertebrae. They 

 increase only gradually in length for the first twenty of the series, and 

 are markedly oblique, with the posterior border stout, and the anterior 

 border alate. With the twenty-sixth they begin to increase more 

 rapidly in length, and have become more nearly vertical in position, 

 and are thinner at each margin. In the thirty-fifth or thirty-sixth they 

 attain their greatest length, and are here directed slightly forwards. 

 Thence to the end of the tail, the length decreases gradually, and, in 

 position, they are directed more and more obliquely backward. The 



