CRYPTODONTIA. 263 



and maxillary are more deeply notched to form its fore and 

 under boundary ; the nasal (15), prefrontal (14), and lacrymal 

 (13), complete that boundary. Below the middle of the orbit 

 a thick, smoothly rounded, vertical ridge projects from the 

 maxillary, in the position of the alveolus of the tusk in Pt. 

 declivis ; but it rather suddenly subsides upon the alveolar 

 border, which is here entire and imperforate, forming simply 

 a low obtuse angular projection upon that border. Sections 

 of fragments of Oudenodon have demonstrated this ridged 

 part of the maxillary to be solid, without the vestige of a 

 germ of a tooth answering to the tusk in Dicynodonts. 

 The rest of the alveolar border, chiefly formed by the pre- 

 maxillary, is toothless and subtrenchant, as in the Dicy- 

 nodont reptiles ; and, the lower jaw presenting the same 

 structure, we have in the present remarkable reptile an eden- 

 tulous Saurian. 



The composition of the skull is essentially the same in 

 Oudenodon as in Dicynodon; and the same affinities may be 

 predicated of it, with such additional approach to Chelonia as 

 the total absence of teeth may indicate. But the double 

 nostril demonstrates the Saurian affinities of the genus. 



Two other species, Oudenodon prognathic and Oud. Greyii, 

 Ow., from the sandstones at the base of the Ehenosterberg, 

 South Africa, are described in the Quarterly Journal of the 

 Geological Society, 1860, p. 55. 



Genus Khynchosaurus, Ow. 



Sp. Rhynchosaurus articeps, Ow.* — The fossils in which 

 the above genus and species of reptile have been based 

 are from the new red sandstone (trias) of Shropshire. They 

 occur at the Grinsill quarries, near Shrewsbury, in a fine- 

 grained sandstone, and also in a coarse burr-sandstone ; in the 

 latter the writer found imbedded some vertebra?, portions of 



* Transactions of the Cambridge Philosophical Society, vol. vii. part iii., 

 1842, p. 355, plates 5 and 6. 



