V 



152 Geological Society. 



cesses are not developed. This character, however, Mr. Owen says, 

 is not peculiar to the Vulturidae. Though the part of the fossil pre- 

 served is eminently characteristic of the class of birds, yet it is not 

 calculated to throw light on the closer affinities of the species to 

 which it belongs : nevertheless it supports rather than affects the 

 determination of the Hunterian specimen. For the apparently ex- 

 tinct bird indicated by these fossils, the name of Lithornis vulturinus 

 is provisionally proposed. 



3. Mr. Owen commences his description of the remains of an ex- 

 tinct species of Serpent found at Sheppey, by pointing out the es- 

 sential characters by which the vertebrae of an Ophidian Reptile are 

 distinguished. 



Vertebras joined enarthrodially by a deep anterior transversely 

 oblong cup and a corresponding prominent posterior ball, and fur- 

 ther articulated by projecting posterior oblique processes, wedged 

 like the carpenter's tenon into a mortice, excavated in the anterior 

 oblique processes of the succeeding vertebra, supporting moreover 

 on each side of the fore part of the body an oblong convexity for 

 the moveable articulation of the rib, can belong, Mr. Owen ob- 

 serves, to no other than a reptile of the Ophidian order. 



One of the specimens described in this portion of the memoir, 

 consists of about 30 vertebrae possessing the above characters ; also 

 of a number of long slender ribs, having expanded concave vertebral 

 extremities cemented irregularly together by a mass of indurated 

 clay, and it forms part of the Hunterian collection of fossils ; an- 

 other specimen, consisting of 28 vertebrae, and some others of less 

 magnitude, belong to Mr. Bowerbank's collection. All the speci- 

 mens, Mr. Owen considers, are referable to the same species, and 

 they were all found at Sheppey. 



The vertebrae in each specimen present the same conformation, 

 and nearly the same size, being equal in this respect to those of a 

 Boa Constrictor 10 feet long. They belong to the ordinary dorsal 

 or costal series, and differ from those of the Boa and Python in their 

 superior length as compared to their breadth and height. The ridge 

 continued from the anterior to the posterior oblique processes on 

 each side is less developed : the oblique processes themselves do not 

 extend so far outwards ; and the spinous process is narrower in its 

 antero-posterior extent but longer. In the first two of these differ- 

 ences, the fossil agrees with the Linnaean Coluber and its subgenera, 

 but differs from the Crotalus ; and in the remaining points it differs 

 from Crotalus, Coluber, Naja and Trigonocephalus. The long 

 and comparatively narrow spine, the outward prolongation of the 

 upper angle of the posterior oblique processes, the uniform convexity 

 of the costal protuberance, the uneven or finely wrinkled external 

 surface of the superior arch of the vertebra, are characters which 

 distinguish these Ophidian vertebrae from those of any other genus 

 of the order with which Mr. Owen has been able to compare them. 

 He therefore proposes to call the species provisionally Palceophis To- 

 liapicus. 



The ribs are hollow as in all land serpents. 



