PSAMMODONTIDiE. 
93 
P. 2507. Type specimen of Pinacodus gonoplax , probably referable 
to the present species. The anterior suture has already 
been noted in P. 2584 c. 
49617. Small tooth, probably of this species; Richmond, Yorkshire. 
Purchased , 1878. 
Copodus spatulatus, Davis. 
1862. Copodus spatulatus (Agassiz MS.), Morris & Roberts, Quart. 
Journ. Geol. Soc. vol. xviii. p. 100 (name only). 
1883. Copodus spatulatus , J. W. Davis, Trans. Roy. Dublin Soc. [2] 
vol. i. p. 467, pi. lviii. fig. 7. 
1883. Copodus cornutus, J. W. Davis, tom. dt. pi. lviii. fig. 1. 
1883. Mylacodus quadratics, J. W. Davis, tom. dt. p. 480, pi. lviii. 
figs. 27, 28. 
(P) 1883. Mylacodus sesamini, J. W. Davis, t. c. p. 481, pi. lviii. fig. 29. 
1884. Copodus cornutus, J. W. Davis, Quart. Journ. Geol. Soc. vol. xl. 
p. 623, pi. xxvii. fig. 22. 
Type. Detached tooth ; British Museum. 
Teeth mostly longer than broad, though sometimes of the reverse 
proportions ; crown comparatively flat; a transverse suture, almost 
straight and sharply curved backwards at its extremities, dividing a 
narrow posterior part of the tooth from the larger anterior portion. 
The postero-lateral angles of the root are extraordinarily produced 
backwards, but the corresponding extensions of the crown are very 
slight or absent. The small hinder portion of the tooth has a nearly 
straight posterior margin, being of equal width throughout. 
The specimens in the collection exhibit every gradation between 
the typical elongate form of tooth and those described under the 
names of Mylacodus quadratus and M. sesamini. The original of 
J. W. Davis’s fig. 27, pi. lviii. loc. cit., is merely a broken and 
abraded crown, and the other specimen shows the base of the 
postero-lateral “horns” of the root. The coronal surface of the 
last-named fossil also shows the slight rugosity erroneously described 
as distinctive in M. sesamini. One of the specimens, broader than 
long, exhibits the narrow posterior portion of the tooth in its natural 
position; and the form of the hinder margin of the type of M. sesamini 
is largely due to fracture. 
Form. $ Loc. Lower Carboniferous Limestone: Armagh, Ireland. 
Tipper Carboniferous Limestone : Yorkshire, Derbyshire. 
Unless otherwise stated, the following specimens are from Armagh, 
and in the Enniskillen Collection. 
P. 2513. Type specimen, figured loc. cit. 
