7 



Uronautes cetiformis, sp. nov. 



The cervical vertebra of this species is of unusual form, being 

 short and transverse, and not wider than deep. In Polycotylus 

 latipinnis this vertebra is much wider than deep, and as long as 

 wide. The neuropophyses are compressed so as to be antero- 

 posterior, and they inclose a rather wide neural canal. The para- 

 pophyses are directed equally downwards and outwards, occupy- 

 ing the position of the angle of a subquadrate outline, since the 

 sides are nearly vertical. The articular faces are slightly concave, 

 and the centrum is perforated vertically by the usual two fora- 

 mina. 



A dorsal vertebra found in immediate proximity to the cervical 

 just described is much like that of the Polycotylus latipinnis. 

 That is, it is exceedingly short antero-posteriorly, and has con- 

 cave articular faces, the concavity with flat fundus, and marked 

 with a few obscure concentric grooves. The sides are also slightly 

 concave, and are pierced with a foramen at the superior portion. 

 The vertical foramina are also present. The neural arch is in 

 this specimen separated from the centrum, not having become 

 coossified. This circumstance might lead to a doubt as to the 

 proper reference of the specimen to this animal, but such doubt 

 has little foundation. In one of the caudal vertebrae one of the 

 diapophyses is coossified, and the other is not. The suture of the 

 surface thus exposed is of a very fine texture, and evidently not 

 like that seen in the genera where it is to act as a permanent 

 articulation. In the case of the dorsal vertebra, the suture for 

 the neuropophysis has the same character. This vertebra is 

 much larger than the cervical, but does not much exceed the 

 proximal caudal in size ; pi'eserving the relations seen in the 

 Polycotylus latipinnis. Adjoining the border of the fossa of the 

 neuropophysis is a small parapophysial tuberosity. 



A proximal caudal vertebra has a very small fore and aft diame- 

 ter, and the vertical exceeds the transverse diameter. The dia- 

 pophyses spring from the middle of the sides of the centrum, 

 while the inferior face is separated from the inferior lateral faces 

 by an obtuse longitudinal angle. In general, the form is that of 

 a transverse hexagon. The chevron facets are very slightly de- 

 veloped. Another probably distal caudal vertebra considerably 

 resembles that in the corresponding part of the skeleton of a 

 cetacean. It is without neural arch, transverse, flat below, and 



