C0CnLI0D0NIID,J5. 
173 
The following specimens may indicate a hitherto unknown 
species : — 
P. 5157-8. Tooth measuring 0-019 in the longer diameter, asso- 
ciated with small teeth; also two associated teeth and 
fragments pertaining to an equally large fish; Fenton. 
Purchased, 1885. 
Genus PLEUROPLAX, nomen nov. 
Syn. Pleurodus, Hancock & Atthey (non Pleuroilon, IN'ood, 1S40, nec 
Harlan, 1842), Nat. Hist. Trans. Northumb. & Durham, vol. iv 
1872, p. 408. 
Kami of jaws meeting at an acute angle; teeth, so far as known, 
mostly fused into continuous transverse plates, few in number, 
carinated, and having indented antero- and postero-latoral borders, 
marking the free extremities of the components. Body depressed, 
covered with fine shagreen ; dorsal fin-spine laterally compressed, 
broad, smooth, or ornamented with delicate longitudinal stri®. 
Pleuroplax rankinei, Hancock & -Itthey. 
1843. Pkwodus rankinei, L. .\gassiz, Poiss.Foss. vol. iii. p. 174 (name 
only). 
1843. Pleurodm affinis, L. Agassiz, loc. cit. (name only). 
18131. Pleurodus uffinis,i, W. .Salter (w Egerton, MS.), loss. S. Welsh 
Coal Field (Mem. Geol. Surv.— Iron Ores Gt. Brit. pt. iii.), p. 225 
pi. i. tigs. 18, 19 (figures only). 
1801. Paieilodas (?) sp., J. W. .Salter (at- Egerton, MS.), loc. cit. 
p. 225, pi. i. tig. 20 (abraded tooth, figure only). 
1872. Pleurodus rankinii, A. Hancock & T. Atthey, Nat. Hist. Trans. 
Northumb. & Durham, vol. iv. p. 408, pi. xv. tig. 1. 
1873. Pleurodus, T. P. Barkas, Coal Meas. I’aheont. p. 18, pi. i. 
figs. 24-27. 
1874. Pleurodus nffnis, W. J. Barkas, Monthly Kev. Dental Surgery, 
vol. iii. p. 0, figs, xxxvi.-xxxix. 
1876. Pleurodus ajfinis, J. Ward, [Proc.] N. Staffs. Nat. Field-Club, 
p. 223. 
1876. Pleurodus rankinii, J. Ward, loc. cit. p. 222, fig. 13. 
1879. Pleurodus affinis, J. W. Davis, Quart. Journ. Gecd. Soc. vol. 
XXXV. p. 181, pi. X. figs. 1-11. 
Type. Associated deutal plates, and anterior portion of body with 
dorsal fin-spine ; Museum of Newcastle-upon-Tyne. 
Axial rounded carina of the dental crown prominent, rarely 
marked by faint transverse sulci ; unabradod coronal surface smooth, 
or with delicate irregular wrinkles near the mai'giu. Anterior 
