COCHLIODONTID^E. 
213 
1855. Cochliodus acutus, F. M‘Coy, Brit. Palaeoz. Foss. p. 621, pi. 3 i. 
fig. 24. 
1862. Deltoptychius acutus, Morris & Roberts, Quart. Joura. Geol. Soc. 
xol. xxiii. p. 100 (name only). 
186/. Cochliodus comp actus, R. Owen, Geol. Mag. yoI. iY. pi. iv. fig. 1. 
1883. Deltopty chius acutus, J. W. DaYis, Trans. Roy. Dublin Soc. [2] 
yoI. i. p. 433, pi. liii. figs. 13-17. 
1883. Deltodus expansus, J. W. DaYis, tom. cit. p. 431, pi. liii. figs. 9,10 
{non fig. 11). 
(?) 1884. Deltoptychius plicatns, J. W. Davis, Quart. Journ. Geol. 
Soc. yoI. xl. p. 628, pi. xxxi. figs. 13, 14. 
(?) 1886. Deltoptychius plicatns, J. W. Daxis, Geol. Mag. [3] yoI. iii. 
p. 152. 
Type. Detached dental plates : AYoodwardian Museum, Cam¬ 
bridge. 
“ Upper ’ dental plate expanded posteriorly towards the inner 
border; the large coronal ridge angulated ; lateral borders raised 
into sharp ridges. “Lower ' plate with the large median ridge 
angulated, sharply separated from the upturned postero-lateral area. 
Form. § Loc. Lower Carboniferous Limestone : Armagh, Ireland, 
and Ayrshire, Scotland. Upper Carboniferous Limestone : York¬ 
shire and Derbyshire. 
(i.) Slightly curved variety (? upper jaw). 
P. 2433-35. Three dental plates described and figured by J. W. 
Daxis, loc. cit. p. 433, pi. liii. figs. 15-17 : Armagh. 
Enniskillen Coll. 
P. 2448—9. Two specimens described and figured as referable to the 
upper jaw of Deltodus expansus, J. W. Daxis, loc. cit. ; 
Armagh. Enniskillen Coll. 
P. 2436. Thirty specimens; Armagh. Enniskillen Coll. 
P. 1455. Four small abraded dental plates; Armagh. 
Egerton Coll. 
28725. Two similar plates ; Armagh. Purchased, 1853. 
46045. Imperfect dental plate probably of this species; Beith, Ayr¬ 
shire. Presented by R. Craig, Esq., 1874. 
(ii.) Inrolled variety (? lower jaw). 
P. 2431-2. Two dental plates desciibed and figured by J. "W. Daxis, 
loc. cit. p. 433, pi. liii. figs. 13, 14; Armagh. 
Enniskillen Coll. 
P. 2437. Twenty specimens; Armagh, 
Enniskillen Coll. 
