68 CHELONIA. 



Lytoloma, sp. 



Syn. Euclastes, sp., Dollo *. 



The mandibular symphysis of this form is relatively wider, less 

 pointed, and more concave than in the next species. The oral 

 surface shows a pair of grooves apparently made by a median epi- 

 dermal shield. 



Hob. Europe (England). 



39113. The imperfect mandible, in matrix; from the Chalk ofHal- 

 (Fig.) ling, Kent. Figured by Owen in his ' Cretaceous Eeptilia ' 

 (Mon. Pal. Soc.), pt. i. pi. vii. a. figs. 4, 5 ; and referred to 

 the present group by Dollo in the passage cited. 



Bowerbank Collection. Purchased, 1865. 



R. 1498. The imperfect symphysis of a similar mandible, from the 

 Chalk; locality unknown. No history. 



35180. The water-worn symphysis of an apparently similar mandible 

 from the Cambridge Greensand. Purchased, 1859. 



30255. The imperfect symphysis of a mandible apparently agreeing 

 with the preceding. Purchased, 1855. 



Lytoloma cantabrigiense, Lydekker 2 . 



Very imperfectly known. Apparently allied in the structure of 

 the mandible to L. trigonic&ps ; mandibular symphysis narrow, 

 pointed, and very flat superiorly. The humerus provisionally referred 

 has the head less oblique than in the typical forms, the radial process 

 with a solid triangular surface, the shaft very much constricted, 

 and the distal border very oblique to the latter. All the specimens 

 indicate a comparatively small form. 



Hab. Europe (England). 



All the following specimens were obtained from the Cambridge 

 Greensand. 



35178. The mandible, imperfect posteriorly. The type specimen. 

 {Fig.) Described and figured by the writer in the ' Quart. Journ. 



Geol. Soc' vol. xlv. pp. 233, 234, fig. 2. All of the arti- 

 cular portion is wanting. Purchased, 1859. 



35179. The symphysis of an apparently similar mandible, with the 



oral surface covered with phosphate. Same history. 



1 Ann. Soc. Geol. Nord, vol. xv. p. 122 (1888). 

 " 2 Quart Journ. Geol. Soc. vol. xlv. p. 233 (1889). 



