172 
SEr.Acnii. 
1872. Ilelodus simplex, Ilancnclc & Atthey, Nat. Hist. Trans. Northumb. 
& Piirhatii, vol. iv. p. 422. 
1875. Ilelodus simplex, J. Ward, [Proe.] N. Staffs. Nat. Field-Olub, 
p. 220. 
1876. Ilelodus simplex, W. .1. Barkas, Monthly Rev. Dental Surgery, 
vol. iii. p. 101, figs, xlv.-xlviii. 
1888. Ilehdus simplex, R. II. Trnquair, Oeol. Mag. [.I] vol. v. p. 84. 
Type. Detached tooth ; British Museum (in part). 
Dental crown very variable in form, but much elevated and 
generally obtuse, attaining a maximum breadth of O'Olo. The 
species is still imperfectly known, and many of the specimens men- 
tioned below are only provisionally assigned to it. 
Form. 4)' Toe. Coal Measures : Staffordshire, Shropshire, York- 
shire, and Northumberland ; South Wales ; Lanarkshire. 
P. 488. Tooth figured by Aga.ssiz, torn. dt. pi. xix. fig. 0 ; Silver- 
dale, Staffordshire. Erjerton Coll. 
P. 2906-7. Two groups of naturally-associated imperfect teeth, 
with remains of cartilage ; Longton, Staffordshire. 
EnmsJciUeii Coll. 
P. 2908. Fragment of trunk, with imperfect dorsal fin-spine ; 
Longton. Eimishillen Coll. 
P. 2909. Six comparatively pointed teeth ; Longton. 
Ennishillen Coll. 
P. 5160. Ten teeth; Longton. Purchased, 1S85. 
P.2910. Four teeth; Fenton, Staffordshire. Ennisldllen Coll. 
P. 5159. Two naturally-apposed series of four small teeth ; Fenton. 
Purchased, 1885 . 
P. 1440. Two teeth ; Fenton and Silverdalo. Egerton Coll. 
21422, 21975. Five detached teeth ; also six smaller teeth naturally 
arranged in two adjoining series, doubtfully assigned to this 
species ; Carluke, Lanarkshire. Purchased, 1847 - 8 . 
P. 2905. Associated teeth ; Carluke. Enniskillen Coll. 
P. 2283. Two teeth; Carluke, 
Presented hy George Griff^ths^ Esq., 1882. 
