BY R. ETHERIDGE, JUN. 411 



neural spine from the upper mai-gin of the canal, in the middle 

 line^ is 3f inches in height, but is shortened by fracture ; it is 

 sharp, thin, and laterally compressed. At its base the spine is 

 1| inches thick, from before backwards, but at the broken upper 

 extremity, the transverse width is a little less than 1 inch. 

 It is very erect, and does not appear to have any posterior 

 inclination, but the posterior zygopophysis would overhang the 

 succeeding centrum to a slight extent when in apposition with 

 it. The neural canal itself is broadly oval, measuring 1 inch in 

 its longest diameter ; but the prezygopophysis is not preserved. 

 The diapophysial suppoi't of the rib visible, is placed very high up, 

 and is directed backwards and upwards, and forms the entire 

 costal surface ; below this point the suiface of the vertebra is 

 much hollowed. The diapophysis is ledge-like, flattened to some 

 extent above and below, with the ridge connecting its under 

 portion to the lateral surface of the centrum very ill-defined. The 

 actual surface for the rib articulation is not preserved through 

 fracture. 



The remains of the ribs consist either of portions of two, or 

 else one broken in half, with the severed ends contiguous to one 

 another. One of these pieces is 6 inches in length, the other 6^ 

 inches, the former practically straight, the latter curved, and both 

 laterally compressed. When united these would represent a rib 

 from 13 to 14 inches long. The third example previously referred 

 to, I'epresents the px'oximal end of a rib, with a simple expanded 

 termination about f of an inch in diameter. 



Taking into consideration the general characters of these bones, 

 and the position of the diapophyses, little douV)t can be entertained 

 that "we are dealing with vertebrae of the dorsal sei-ies. In 

 describing those of Plesiosaurus dolichodeh'us, Oonyb., Owen says 

 — "The transition from the cervical to the dorsal series is effected 

 by the usual elevation of the costal surface by gradational steps, 

 continued through about five vertebrse, until a single costal surface 

 is presented by a large diapophysis from the neural arch."* This 



* Mon. Foss. Reptilia Lias. Form. 1865, pt. 1, p. 6. 



