28 
TERTIARY VERTEBRATA OF THE FAYtTM. 
pair of hypapoj)liysial ])roininences is jireseiit, and the neural spine is represented 
by a W -shaped thickening. 
In the last cervical (text-fig. 10, E) the slightly biconcave centrum is still short, 
somewhat more so dorsally than ventrally ; it is oval in outline. The neural 
spine is represented by a blunt ridge. Behind the pedicle of the neural arch 
there is a deep groove running down from the neural canal behind the transverse 
process, which is here imperforate and has a blunt tuberous extremity. On the 
Cervical vertebrae of Arsinoitherhim zitteli : A, third cervical, from front; R, fifth cervical, from front; 
C, fourth cervical, from front ; D, ditto, from right side ; E, seventh cervical, from front. 
a.z., anterior zygapophyses ; dj)., diapopliysial bar ; hp., hypapojdiyses ; 7i.sp., neural spine ; pj^., ])arapo- 
physial bar ; p.^., posterior zygapophyses ; tp., transverse processes ; v.c., vertebrarterial canal. nat. size. 
hinder border of the centrum near its ventral angles is a jtair of facets for tlie 
heads of the first ])air of ribs. These facets are continuous posteriorly with the 
posterior face of the centrum and look outwards, backwards, and downwards. 
The thoracic series is not completely known. In the anterior region (text-fig. J 1 ) 
the centrum is wider tlian high ; its anterior face is flat, while the posterior face is 
