95 
CHIROCEXTEID^. 
/ t . • 
Portheus ma|itelli 9 Xewton. 
1822. “ Unknown fish/’ G. A. Mantell, Foss. Soutli Downs, p. 241, 
pi. xlii. figs. 1, 3, 4. 
1835. yiegalodon sauroides, L. Agassiz, Poiss. Foss., Feuill. p. 55 
(name only). 
1836. Megalodon ? leicesiensis, G. A. !Mantell, Descript. Catal. Geol. 
&c. 5Ins. Sussex Sci. Lit. Inst, ecl.%, p. 30. 
1837-44. Hypsodon lewesiensis, L. Agassiz, Poiss. Foss. vol. y. pt. i. 
p. 100 (in part), pi. xxv b. figs. 1, 2. 
1877. Portheus mantelli, E. T. Xewton, Quart. Journ. Geol. Soc. 
vol. xxxiii. p. 510. 
Type. Imperfect left maxilla and premaxilla ; British ACiiseiim. 
A species of moderate size, the upper jaw attaining a length of 
about 0*18. Premaxilla with five teeth of unequal size, lyiaxilla 
about four times as long as the premaxilla, and its oral border in 
the form of a slightly concave arch. Teeth smooth, not facetted. 
Form. Loc. Turonian : Sussex. 
4066-67. Type specimen, the premaxilla being in counteiqDart; 
Chalk, Lewes. Alantell Coll. 
Portheus daviesi^ Xewton. 
1877. Portheus damesii, E. T. Xewton, Quart. Journ. Geol. Soc. 
vol. xxxiii. p. 511, pi. xxii. fig. 13. 
Type. Bight maxilla; British Museum. 
A'species of moderate size, knoAvn only by the maxilla, which is 
unusually robust and exhibits a slightly convex oral border. The 
teeth are smooth and not facetted, largest in the middle of the bone 
at the summit of the convexity. 
Form. Loc. Turonian : Kent. 
28388 . Type specimen, the right maxilla associated with a ver¬ 
tebral centrum and an imperfect undetermined bone; 
Lower Chalk, near Maidstone. Mantell Coll. 
Portheus gaultinus, Xewton. 
[Text-figure 5.] 
1877. Porfheeus gaultinus, E. T. Xewton, Quart. Journ. Geol. Soc. 
vol. xxxiii. p. 512, pi. xxii. figs. 1-12, and woodcut. 
Type. Imperfect head and associated vertebrae ; Museum of 
Practical Geology, London. 
A species of moderate size, the cranium attaining a length of 
about 0*2. Premaxilla with five teeth, the second and third much 
larger than the others. Maxilla four times as long as the pre- 
