Manchester Memoirs, Vol. liv. (1909), /V(). 4 3 



is very different from P. Cramptom, and I think cannot 

 be included in the same genus. 



" Plesiosaunis " Zeilandi, Phillips. 



Type skeleton in the York Museum. 



This species is quite unknown, no figures of it having 

 ever been given ; as I have not yet examined it in detail, 

 I do not wish to criticise Lyddeker's attribution of it to 

 the genus Thaumatosmirus. 



" Plesiosaurus " longirostris, Blake. 



This species was described from a somewhat restored 

 skeleton in the possession of Mr. Brown Marshall, of 

 Whitby. I have not so far been successful in discovering 

 its present whereabouts. 



Blake's description is very slight, but he suggests that 

 it is the same as Owen's P. coelospondyliis. 



It is possible that this species may include a some- 

 what fragmentary skeleton in the Manchester Museum, 

 which is described below as the type of a new genus and 

 species Sthenarosaurus Dawkiiisi. 



Plesiosaurus coelospondyhis, Owen. 



This species founded on a series of cervical vertebrae 

 in the Whitby Museum, which can no longer be found, 

 must rank as undefined, as it is quite impossible to recog- 

 nise the type from Owen's description. Several other 

 species do actually occur in the Upper Lias of Whitby, 

 but are only represented by small sets of vertebrae some- 

 times associated with other bones. Such remains in the 

 Manchester and Whitby Museums indicate at least three 

 other very distinct species. 



From the above account it will be seen that our 

 knowledge of the Upper Liassic Sauropterygia is really 



