40 
actinopttsrygii. 
Pachyrhizodus gardneri (Mason). 
1837-44. Bypsodon lewesiensu, L. Agassiz, Poiss. Foss., Feuill. p. 104 ' 
razftu'J' p4 ; '• p " ®?> P 1 - figs- 2, 4, pi. xxv b. figs. 6, 7 (in P^)- 
i sfto* < R T '‘ ° r Fwh ’” T ‘ Sniitl1 ' L( >nd. Geol. Journ. p. 21 , & woodc- 
lm). Acroflonfns,,unK gardneri, ,T. W. Mason, Quart. Journ. Geol- 
_ S °e. vol. xxv. p. 444, pi. xix. 
1877. Hypsodtm tewtsiemis, E. T. Newton, Quart. Journ. Geol. Soc. 
vol. xxxin. p. 508. 
1888. Pachyrhizodus gardneri, A. S. Woodward, Proc. Geol. Assoc. 
vol.x. p. 314. ’ 
Type. Portion of mandibular ramus ; British Museum. 
urge species, the mandible attaining a length of at least 0’3- 
Dentigerous portion of premaxilla nearly half as hroad as long, i* 
marginal teeth not inclined outwards, its inner teeth with much' 
expanded base, very stout and curved inwards. Dentary bone very 
deep but rapidly contracting in front into a narrow thickened 
symphysis, and sharply bent inwards in the lower two-third* 
throughout Us length; its maximum depth equal to the base-line 
ot 6 anterior teeth; a small groove on tho outer face extending 
from the middle of the symphysial border in a longitudinal direc- 
tion and slightly upwards until lost at the oral- border; the stout 
incurved teeth somewhat over 20 in number if all were present. 
Form, cj- Uc. Turonian : Kent and Sussex. 
4105. Fragmentary remains of jaws in a block of chalk, partly 
noticed and figured by Agassiz, tom. cit. p. 99, pi. xxv«- 
gs. 4, among the type specimens of Hypxodon lew^ en 
Chalk, Lewes. There are portions of the dentary 
of both sides, that of the left only shown in the fig ure ' 
the characteristic premaxilla of the left side, much 
fractured, is exposed from the oral aspect and display® 
the two large inner teeth besides two of the marginal 
ee . Remains of the left maxilla exhibit a series o 
smaller teeth. ]Jantd l Coll- 
4 16 74. Slab of chalk with scattered remains of head, noticed by 
loulmin Smith, he. cit. 1846; Lower Chalk, Kent- 
• m ° n ? 44le fragments of jaws the most conspicuous is th® 
imperfect right dentary, exposed from within and parti)’ 
shown in Smith's upper figure, he. cit. The teeth on this 
ne are large and smooth, curved inwards, and arrange 
m very close series, the base of each much thicker 
t • j Ur< " , * roTT1 ' 4s enter to its inner face than from si e 
6 ? t e aheolar border is greatly thickened to supp° r 
