ACICHELYID^J. 153 



perfectly ossified distally ; neurals with short antero-lateral surfaces ; 

 middle and hinder neurals forming a strongly marked tectiform 

 ridge, with a chevron-like (/^) cross-section ; 5th neural (fig. 37) 

 with postero-lateral surface deeply excavated for the reception of a 

 process of the costal. Vertebral shields broad, with the periphery 

 of the underlying areas very boldly fluted. 



On the ventral aspect of the anterior neurals the antero-lateral 

 surfaces become very large, thus indicating an approximation to the 



Fig. 37. 



Pelobatochelys blakei— The fifth neural bone ; from the Kimeridge 

 Clay of Dorsetshire, f. 



A specimen from the Kimeridge Clay of Weymouth, formerly in 

 the collection of the late Mr. Damon, shows the contour of the 

 entire carapace, although the individual bones are not definable. 

 The contour is cordiform, and the neural region forms a sharp ridge, 

 with the costals sloping away like the sides of a roof. 



Pelobatochelys blakei, Seeley \ 

 The type and only described species. Attains large dimensions, 

 but is very imperfectly known. 

 Hab. Europe (England). 



R. 2. Fragment of the anterior portion of the carapace, showing the 

 {Fig.) first three neurals and parts of the adjacent costals, of an 

 immature individual ; from the Kimeridge Clay of Wey- 

 mouth, Dorsetshire. One of the types ; figured by Seeley 

 in the ' Quart. Journ. Geol. Soc' vol. xxxi. pi. xiii. fig. 1. 

 On the ventral aspect the anterior lateral facets of the 

 second and third neurals exceed half the length of the 

 postero-lateral facets ; whereas in the type of Acichelys 

 redenbacheri figured by Meyer in his ' Eept. Lith. Schiefer,' 

 pi. xxi. fig. 4, there are no distinct antero-lateral facets. 



Purchased, 1880. 



1 Quart. Journ. Geol. Soc. vol. xxxi. p. 234 (1875). 



