Peterson and Gii.more: Elosaurus Parvus. 



497 



ing in a trianjj^ular end to which the cervical rib ])roI)al)ly attached 

 though there are no other evidences of the latter. This process is 

 supi^orted inferiorl)- by the inferior blade of the diapophysial lamina. 

 The superior bkule is absent. Of the (lia])0ph\-sial cavities the post- is 

 the most pronounced, the pre- and supra- being very shallow, while 

 the infradiapoph\sial cavity is wanting. See Fig. 7. 



Mkasuremunts. 



Greatest length anterior to posterior zygapophyses, 60 mm. 2^ inches. 



Top of spine to inferior border of neural arch, 35 " 1% " 



The Dorsals. — The presence of the heavy capitular facets situated 

 far down on the anterior border of the neural arch, together with the 

 presence of a single spine would indicate that this vertebra l^elonged 

 well back in the dorsal series. 

 The spine which wants the su- 

 perior portion has a posterior 

 position. The superior blades 

 of the postzygapophysial laminae 

 are very heavy while the inferior 

 are of weaker construction and 

 descend to form the posterior 

 walls of the neural canal. The 

 transverse processes are well ex- 

 panded and extend upward and 



forward as shown in Figs. 9 and lamina ; pzl., postzygapophysial lamina ; 



Fig. 8. Dorsal of Elosazirus parvus. 

 Anterior view (No. 566), one half natural 

 size. s., spine; azl., prezygapophysial 



10. The tul)ercular facet is 

 much restricted in comparison 

 with the extended capitular ar- 

 s 



Fig. 9. I'osterior view of same (No. 

 566). One half natural size, /-z-, pos- 

 terior zygapophysis. 



///., horizontal lamina; dl., diapophysial 

 lamina; /., transverse process; a.z., an- 

 terior zygaphophysis ; c.f. , capitular facet. 



ticulation. The diapophyses are 

 sujjported superiorly by very 

 weak diapophysial laminae ; in- 

 feriorly these laminae divide into 

 two branches, one part descend- 

 ing obliquely backward to a point 

 half way down on the neural 

 arch, while the weaker branch '•• 

 meets the heavy prezygapophy- 

 sial laminae just above the capit- 

 ular facet, as is shown in Fig. 



8 If the complete dorsal series were known so that the development of the laniinoe 

 could be traced, this branch might prove to be a division of the horizontal laminre as 

 shown by Hatcher in his description of the dorsals of Diplodocus. 



