10 
ICHTHTOTOIII. 
Pleuracanthus tenuis, J. W. Davis, Quart. Journ. Gcol. Soc. 
vol. xxxvi. (1880), p. 327, pi. xii. fig. 1. — Lower Coal- 
Measures ; near Halifax, Yorkshire. 
Pleuracanthus wardi, J. W. Davis, tom. cit. p. 334, pi. xii. fig. 6. 
— Coal-Metisures (Ilagminc) ; Penton, N. Stafibrdshire. 
Two small spines, from the Devonian of llussia, have been erro- 
neously referred to this genus — the one named P. taberculatus 
(E. d’Eichwald, Bull. Soc. Imp. Nat. Moscou, vol. xix. 1846, no. iv. 
p. 293, pi. X. figs. 8, 9), the other P.porosus (E. d’Eichwald, Lethma 
Rossica, vol. i. (1860), p. 1607, pi. Iv. fig. 8). 
III. Species fowuled upon teeth. 
Diplodus gibbosuS) Agassiz. 
1841. Diplodus ffiblmus, E. W. Hiuney, Trans. Manchester Geol. Soc. 
vol i. p. 169, pi. V. tigs. 17, 18 (name and figure only). 
1843. Diplodus gihbosus, L. Agassiz, Poiss. Foss. vol. iii. p. 204, pi. 22 b. 
fig. 1 (non figs. 2-6) (B.M. Coll.). 
(?) 1843. Diplodus minutus, L. Agassiz, tom. cd. p. 205, pi. 22 b. figs. 6-8. 
1861. Diplodus gibbosus, W. C. Williamson, Phil. Trans, p. 680. 
1807. Dittodus paralklus, R. Owen, Trans. Odontol. Soc. vol. v. p. 326, 
pi. i. 
1807. Dittodus divergens, R. Owen, tom. cit. p. 3.34, pi. ii. 
1867. Ochlodus crassus, R. Owen, toyn. cit. p. 340, pi. v. 
1807. Aganodus apicalis, R. Owen, tom. cit. p. 369, pi. ix. 
1867. Aganodm undalus, R. Owen, tom. cit. p. 302, pi. x. 
1867. Plernodus productm, R. Owen, tom. cit. p. .363, pi. xi. 
1870. Diplodus giblmsus, A. Hancock & T. Atthey, Nat. Hist. Trans. 
Northumberland and Durham, vol. iii. p. 111. 
1876. Pleuracanthus (Diplodus) gibbosiis, J. Ward, [Proc.l North Staffs. 
Nat. Field-Club, p. 224. 
Type. Detached tooth ; British Museum (P. 497). 
Teeth having principal cones of the crown divergent, compressed, 
with lateral carinm, sometimes delicately serrated ; median denticle 
short, compressed, and slender, and posterior “ button ” prominent. 
Form. hoc. Coal-Measures : Northumberland, Lancashire, Staf- 
fordshire. 
P. 497. Type specimen ; Silverdale, S. Stafiford shire. Egerton Coll. 
P. 1724. Fragments of teeth ; Silverdale. Egerton Coll. 
46294. Eleven teeth ; Longton, N. Stafibrdshire. 
Presented by John Ward, Esq., 1874- 
46029. Three teeth of a small variety, with very divergent prin- 
cipal cusps, doubtfully of this species ; Longton. 
Presented by John Ward, Esq., 1874. 
P. 1725. Two teeth from Deep-mine shale; Longton. Egerton Coll. 
