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XXI. — Description of some Ophidiolites (Palseophis toliapicus) from the 

 London Clay at Sheppey, indicative of an extinct species of Serpent. 



By RICHARD OWEN, Esq., F.R.S., F.G.S. 



Plate XXII. 



W HILST recording the evidences of the warm-blooded Vertebrates which have 

 been found in the London Clay, I take the opportunity of describing some fossils 

 from the same formation, referable to an order of reptiles which appears to have 

 been very sparingly represented in the fauna of former periods of the history of the 

 earth. 



Vertebrae joined enarthrodially by a deep anterior transversely oblong cup and a 

 corresponding prominent posterior ball, and further articulated by two projecting 

 posterior fiat oblique processes wedged like the carpenter's tenon into a mortice 

 excavated in the anterior oblique processes of the succeeding vertebra ; supporting, 

 moreover, on either side of the fore-part of the body, an oblong convexity for the 

 moveable articulation of the rib, belong unequivocally to a reptile of the Ophidian 

 order. 



A group of about thirty vertebrae of this description, with a number of long and 

 slender ribs, having expanded concave vertebral extremities, cemented irregularly 

 together by a mass of indurated clay, forms part of the choice collection of fossils 

 left by John Hunter, and now in the Museum of the Royal College of Surgeons, 

 London*. 



A portion of the spinal column of apparently the same species of Serpent, mea- 

 suring eighteen inches in length, and including twenty-eight vertebrae ; a smaller 

 group of seven vertebrse, and a few detached ones, are contained in the museum of 

 Mr. Bowerbank. 



All these specimens are from the Isle of Sheppey. 



The vertebrse in each specimen present the same conformation and nearly the 

 same size : they are as large as those of a Boa Constrictor ten feet in length. They 

 belong to the ordinary dorsal or costal series, but differ from the vertebrse of both 

 Boa and Python in their superior length, as compared with their breadth and 



* This specimen is here described and figured by permission of the Museum Committee of the Royal 

 College of Surgeons. 



VOL. VI. SECOND SERIES. 2 E 



