■ / 
pJ^rAJja-C. sesv£en2r. /F/t^Fsc'C, 
-z4nz. cAA v /F&J' , /?/*?, ^~~^ ? 9 S * A .Alr^r*/<asx. - f JlefeL&A., /J-i^^yO- - 
Pleuracanthus tenuis , J. W. Davis, Quart. Journ. Geol. 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-Measures (Eagmine) ; Denton, N. Staffordshire. 
Two small spines, from the Devonian of Eussia, have been erro¬ 
neously referred to this genus—the one named P. tuberculatus 
(E. d’Eichwald, Bull. Soc. Imp. Hat. Moscou, vol. xix. 1846, no. iv. 
p. 293, pi. x. figs. 8, 9), the other P.porosus (E. d’Eichwald, Lethoea 
Eossica, vol. i. (1860), p. 1607, pi. lv. fig. 8). 
III. Species founded upon teeth . 
Diplodus gibbosus, Agassiz. 
1841. Diplodus gihhosus, E. W. Binney, Trans. Manchester Geol. Soc. 
vol. i. p. 169, pi. v. figs. 17, 18 (name and figure only). 
1843. Diplodus gibbosus, L. Agassiz, Poiss. Foss. vol. iii. p. 204, pi. 22 b. 
fig. 1 (non figs. 2-5) (B.M. ColL). 
(P) 1843. Diplodus minutus , L. Agassiz, tom. cit. p. 205, pi. 22 b. figs. 6-8. 
1851. Diqolodus gibbosus, W. C. Williamson, Phil. Trans, p. 680. 
1867. Dittodus parallelus, E. Owen, Trans. Odontol. Soc. vol. v. p. 325, 
pi. i. 
1867. Dittodus divergens, E. Owen, tom. cit. p. 334, pi. ii. 
1867. Ochlodus crassus, E. Owen, tom. cit. p. 346, pi. v. 
1867. Aganodus apicalis , E. Owen, tom. cit. p. 359, pi. ix. 
1867. Aganodus undatus, E. Owen, tom. cit. p. 362, pi. x. 
1867. Pternoclus productus, E. Owen, tom. cit. p. 363, pi. xi. 
1870. Diplodus gibbosus, A. Hancock & T. Attliey, Nat. Hist. Trans. 
Northumberland and Durham, vol. iii. p. 111. 
1875. Pleuracanthus (Diplodus) gibbosus, J. Ward, [Proc.] 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 carinse, sometimes delicately serrated; median denticle 
short, compressed, and slender, and posterior “ button” prominent. 
Form. § Loc. Coal-Measures: Northumberland, Lancashire, Staf¬ 
fordshire. 
P. 497. Type specimen ; Silverdale, S. Staffordshire. Egerton Coll .. 
P. 1724. Fragments of teeth ; Silverdale. Egerton Coll. 
46294. Eleven teeth; Longton, N. Staffordshire. 
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, 
