﻿SUPPLEMENT (No. VII) 



TO THE 



MONOGRAPH 



ON 



THE FOSSIL EEPTILIA 



OF 



THE WEALDEN AND PURBECK FORMATIONS. 



(POIKILOPLEURON and CHONDROSTEOSAURUS.) 



Order. CROCODILIA. 



Family. CCELOSPONDILIA. 1 



Genus — Poikilopleuron. Eudes-Deslongchamps." Plate I. 



This genus was established on fossils discovered in the Oolitic building-stone at Caen, 

 Normandy, and the characters which have led to the recognition of evidences of the 

 genus in our own Weal den deposits are the shape and texture of the vertebrae, and more 

 especially the latter. By these were determined a caudal vertebra from the Wealden of 

 Tilgate, in the Mantellian collection, now in the British Museum : which vertebra differed 

 from the type-specimens on which the genus was founded, only by a slight inferiority of 

 size. 



M. Deslongchamps assigns the length of a 'decimetre/ or thereabouts, to his vertebrae, 

 say 3 inches, 10 lines. The Wealden specimen, which has been fractured across the 

 middle of the centrum, gives a length of that element of 3 inches, 8 lines ; or about 9 

 centimeters. The vertical diameter of the articular end is 2 inches, 3 lines (58 mm.), 

 the transverse diameter is 2 inches, 2 lines (55 mm.) ; the transverse diameter of the 

 middle, contracted part of the centrum is 1 inch, 4 lines (36 mm.)- 



1 This term refers to the large vacuity in the centre of each vertebral body, simulating a medullary 

 cavity ; ossification is here arrested at the middle, not, as in the Amphicoeliu, at the two ends of the 

 centrum. 



2 'Memoires de la Societe Linueenne de Normandie,' vol. vi, 1838, p. 37. 



7 



