LABFvlD^. 
551 
Egertonia isodonta^ Cocchi. 
1866. Egertonia isodonta, I. Cocchi, loc, cit. p. 122, pi. iv. figs. 1, 2. 
Type. Convex (upper) pharyngeal dentition ; British Museum. 
The type species, with all pharyngeal teeth hemispherical, and 
the dental plate measuring as much as 0'025 antero-posteriorly. 
Form. ^ Loc. Lower Eocene (Loudon Clay); London Basin. 
38814. Type specimen, figured loc. cit. pi. iv. fig. 2 ; Sheppey. 
BowerhanTc Coll. 
P. 587. Concave (lower) pharyngeal dental plate, described and 
figured loc. cit. p. 123, pi. iv. fig. 1; Sheppey. 
Egerton Coll. 
28713 a. More imperfect specimen; Sheppey. Purchased, 1853. 
The following species has also been described, but is not repre¬ 
sented in the Collection:— 
Egertonia gosseleti,-^?^. Leriche, Ann. Soc. Geol. ]N[ord, vol. xxix. 
(1901), p. 175, pi. i. fig. 1.—Lower Eocene; Cuis, Epernay, 
Marne. [Upper pharyngeal dentition; University of 
Lille.] 
Genus PLATYLiEMUS, Dixon. 
[Geol. Sussex, 1850, p. 205.] 
An extinct genus, known only by the pharyngeals, each nearly 
or completely covered by a crushing plate, which consists of coarse 
vascular dentine invested with a very thin layer of ganodentine. 
Upper pharyngeal bones separate. 
Platyleemus colei, Dixon. 
1850. Platulcemus colei, F. Dixon, Geol. Sussex, p. 205, pi. xii. figs. 
11-13, pi. X. fig. 23. 
Fjpe. Lower pharyngeal; British Museum. 
The type species, with triangular lower pharyngeal somewhat 
more than two thirds as long as broad. Upper pharyngeal dental 
plate slightly concave. 
Form. ^ Loc. Middle Eocene : Sussex. 
25692. Lower pharyngeal dental plate, figured by Dixon, op. cit. 
pi. xii. fig. 12, to be regarded as the type specimen; 
Bracklesham Beds, Bracklesham, Sussex. Lixon Coll. 
