ADDENDA. 



Incert^i SEDIS. 



Genus STEGOCHELYS, Lydekker 1 . 



A provisional genus, characterized by the complete roofing of the 

 temporal fossa, in which the postfrontal forms a long junction with 

 the parietal, and by the deep notch in the lateral wall of the cra- 

 nium immediately behind the maxilla. The type skull, which now 

 appears to be lost, is represented with distinct nasals, but it is 

 doubtful if this is really the case. 



If the second of the undermentioned specimens really belong to 

 this genus, the latter would appear to be referable to the AcieJiehjidce, 

 and may be identical with one of the Kimeridgian genera. 



Stegochelys planiceps (Owen 2 ). 



Syn. Chelone planiceps, Owen 3 . 



The type species. Of large size, the length of the cranium being 

 0,090 (3-55 inches). 



Hdb. Europe (England). 



R. 1672. Fragment of rock exhibiting the ventral aspect of the im- 

 perfect mandible ; from the Portland Oolite of the Isle of 

 Portland. This specimen, of which the symphysis is 

 entire, precisely resembles the mandible of the type skull 

 from the same deposits, figured by Owen in his ' History 

 of British Fossil Eeptiles,' Chelonians, pi. viii. figs. 1-3. 

 Presented by G. Clifton, Esq., 1889. 



1 art. Journ. Geol. Soc. vol. xlv. p. 229 (1889). 



2 Kep. Brit. Assoc, for 1841, p. 168 (1842).— Chelone. 3 Loc. tit 



