a Pachypod from the Cambridge Upper Oreensand. 315 



light on the Dinosaurian affinities attributable to direct de- 

 scent, but only demonstrates in the living reptiles collateral 

 divergences from fossil types which have still to be discovered. 



But one phalange was found with the metapodium ; it, too, 

 recalls the phalange of an elephant, being like the second in 

 the compression of the distal articulation from above down- 

 ward, and in the shortness of the bone from front to back. As 

 preserved, the proximal articulation measures If inch from 

 side to side, while the distal articulation measures If inch 

 from side to side. The posterior articulation is transversely 

 ovate, slightly concave, and, as preserved, measures an inch 

 from above downward in the middle ; but both articulations 

 are worn ; the distal articulation does not measure | of an inch 

 from above downward. The bone is more compressed on its 

 right side than on the left ; and the right measures less from 

 front to back than the left side, the rig-lit side being 1^ inch, 

 and the left about an eighth of an inch more. Among reptiles 

 only Chelonians have phalanges of this shape. 



The vertebrse associated with these foot-bones are all caudal. 

 The earliest in sequence of the series preserved may be re- 

 garded as one of the earlier caudals ; for relatively to the others 

 the centrum is shorter and deeper, the transverse process and 

 neural arch (which is not preserved) had a stronger attach- 

 ment, and the facets for the chevron bone on the hinder mar- 

 gin were wider apart and larger. The anterior articulation is 

 the more concave of the two, and has a central boss similar to 

 that seen in Pliosaurs and certain Plesiosaurs. The outline 

 of the posterior end of the centrum is a depressed pentagon, 

 measuring about 2^ inches from above, and more than 2| 

 from side to side where widest. From front to back the 

 centrum measures 2 inches. 



The second bone of the series is in much better preserva- 

 tion : it measures 2\ inches in length ; and the posterior arti- 

 culation is not so much larger than the anterior articulation. 

 The neural arch is not preserved ; but the broken attachment 

 of the neurapophysis is lenticular, about an inch long and a 

 \ of an inch wide, and placed equally distant from the anterior 

 and posterior margins. The space between the neurapophyses 

 is concave and a little excavated. External to the neural arch 

 on the shoulder of the centrum on each side is a prominent 

 ridge, Avhich arises about f of an inch from the anterior mar- 

 gin (where they are If inch apart) ; they are prolonged hori- 

 zontally backward, becoming rather more marked and slightly 

 diverging ; they make the lateral spaces both above and below 

 them to be concave. Rather lower below this pair of ridges 

 than they are bellow the neural arch is a second horizontal 



24* 



