354 



THE PORTLAND OOLITE PERIOD. 



CHAP. 



p. 353) was obtained at Swindon, 26-8 inches long, and 11-5 broad. 

 Others were found at Shotover 18-5 and 19-5 long, and 8-0 and 8-5 

 broad. Tibial, fibular, tarsal, and phalangal bones corresponding 

 to those from Market- Rasen occur at Shotover. 



PLEIOSAURUS MACROMERUS. n.s. 



The largest of the swimming reptiles found in the Kimmeridge 

 clays near Oxford rivals in magnitude the great animal buried in 

 the same strata in Dorsetshire. Huge paddles belong to both, but 

 in neither situation is a complete skeleton known. 



The cutting of the Great Western Railway laid open many 

 interesting reliquiae in the Kimmeridge clay near Swindon, and 

 among them vertebrae, and leg bones of several large reptiles. 



One of the leg bones, as already mentioned, belongs to Pleio- 

 saurus brachydeirus ; but there is another of larger dimensions and 

 different proportions, to which it seems probable that several 

 characteristic large vertebrae ought to be associated, so as to con- 

 stitute a well-founded separate species. 



Of cervical vertebrae which appear to belong to this species we 

 have six, from the anterior part of the neck, which, taken in order 

 of magnitude, present the following dimensions. Two of them are 

 from Swindon, and four from Shotover : 



. Length, 2-0 inches ; breadth, 3-4; height, 3-1. 

 2-0 , 3-6 , 3-4. 



4'4 



ft 

 & 



c. 



/ 



27 

 2-8 

 2-8 



5-5 



57 

 5'7 



5-3- 



Swindon. 

 Shotover. 

 Swindon. 

 Shotover. 

 Shotover. 

 Shotover. 



If length be taken at 100, breadth = 192, and height 185. 



Diagram CXL VIII. Anterior cervical vertebra of Pleiosaurus macromerus. 



Scale one-fifth of nature, 

 i. Seen in front. 2. Lateral view. 



