CHIMJERIDJ3. 
63 
surface below and behind the apex of the anterior outer tritor. 
V) Palatine tooth with the posterior inner tritor of large size, and the 
median tritor not extending further forwards than this ; outer tritor 
much elongated and extending far forwards. 
Form. Sf Log. Kimmeridge Clay: Boulogne, N. Prance. 
32416. Left mandibular tooth, probably referred to by Sauvage, 
op. cit. p. 74. Purchased, 1857. 
32767. More imperfect large specimen, of the right side. 
Purchased , 1857. 
32768. Bight palatine tooth. Purchased , 1857. 
Ischyodus beaumonti, Egerton. 
1843. Chimcera ( Ischyodus ) beaumonti, Sir P. Egerton, Proc. Geol. 
Soc. vol. iv. pp. 155, 156. 
1843. Chinuera ( Iscliyodon) beaumontii , L. Agassiz, Poiss. Foss. vol. iii. 
p. 346. 
1847. Ischyodus, Sir P. Egerton, Quart. Journ. Geol. Soc. vol. iii. 
p. 351, pi. xiii. fig. 1. 
1866. Ischyodus beaumontii , E. T. Haray, Bull. Soc. Geol. France, [2] 
vol. xxiii. p. 655, woodc. fig. 1. 
1867. Ischyodus beaumontii, H. E. Sauvage, Catal. Poiss. Form. 
Second. Boulonnais (Mem. Soc. Acad. Boulogne, vol. ii.), p. 83, 
pi. iv. figs. 4, 5. 
(?) 1867. Ischyodus riyauxi, H. E. Sauvage, ibid. p. 76, pi. iv. figs. 14, 
15. [Mandibular tooth ; Boulogne Museum.] 
1890. Ischyodus beaumonti, Woodward & Sherborn, Cat. Brit. Foss. 
Vertebrata, p. 105. 
Type. Bight palatine tooth. 
(?) Mandibular tooth with a very gently wavy oral margin, a 
short post-oral margin nearly parallel to the symphysial, and the 
beak more or less produced and acute ; beak-tritor small, elongated 
antero-posteriorly, with one or two minute tritors immediately 
within; both outer tritors present, though small; median tritor 
very large and broad, occupying the greater portion of the oral as¬ 
pect and nearer the post-oral than the symphysial margin. Pala¬ 
tine tooth with the posterior inner tritor of large size, and the median 
tritor not extending so far forwards as this; outer tritor somewhat 
elongated. (?) Vomerine tooth relatively deep, with a series of small 
tritors. 
The mandibular tooth assigned to this species is described by 
Sauvage under the name of I. riyauxi. 
Form. 6f Loc. .Kimmeridge Clay : N. France and Dorsetshire. 
