I860.] 



OWEN VERTEBRAE FROM FROME. 



493 



the vertebra there appears to be a smooth non-articular short tract 

 between the two expanded par- and di-apophysial surfaces, indica- 

 ting that a bifurcate head of a rib had been attached to the side of 

 this vertebra. 



The neurapophyses are anchylosed to the whole length of the 

 centrum, and incline outward, as they ascend, before bending to- 

 ward and blending with each other above the neural canal, figs. 1 

 & 2, n. The arch, in breadth and height, shows diameters much 

 greater than hose of the centrum itself; the width of the neural 

 canal is more than double that of the body of the vertebra, indica- 

 ting, therefore, either a spinal chord of mammalian proportions, or 

 one which, as in certain lizards and fishes, was surrounded by a 

 largely developed arachnoid and wide venous sinuses. Both the 

 anterior and posterior margins of the arch are concave, the latter, 

 fig. 3, n, most so, indicative of very wide " conjugation-holes " for 

 the exit of the spinal nerves and blood-vessels. 



The anterior zygapophyses, figs. 1, 3, 4, z, ridge-like at their origin, 



Figs. 1-5. — Different views of one of the small Vertebrce found by 

 Mr. O. Moore in a Triassic (?) Deposit in a Fissure of the Moun- 

 tain-limestone near Frome. Magnified 8 diameters. 



Fig. 1. Anterior view. 

 Fig. 2. Posterior view. 

 Fig. 3. Lateral view. 



Fig. 4. Superior view. 

 Fig. 5. Inferior view. 



extend obliquely outward and forward, as far as the vertical parallel 

 of the fore part of the centrum : they form the anterior angles of the 

 neural arch, and have their articular surfaces at the upper part, of an 

 oblong shape, looking upward and a little inward, being very slightly 

 concave. The anterior margin of the arch between them makes a 

 slight projection near the process, and there describes a subangular 

 concavity, the apex of which is at the fore part of the base of the 

 neural spine. This spine rests on the anterior two-thirds of the mid 

 line of the arch ; its summit is broken off; behind it is a low but 

 distinct sharp ridge, between the posterior zygapophyses. These 

 (figs. 3, 4, z') diverge, and slightly descend, projecting a little beyond 

 the posterior surface of the centrum. The area of the neural canal 



