BUFFALO SOCIETY OF NATURAL SCIENCES 15 
long, nearly straight, cylindrical, blunted, main tooth, on one 
side of which are two blunted denticles with small- knobs at 
their summits.” 
This species, like Prioniodus recedens, may have a variable 
number of subsidiary denticles, or none at all. I figure on Plate I, 
two of the latter kind. Figure 12 on the same plate which, how- 
ever, probably represents a form of Prioniodus recedens, shows 
the knob-like denticles which, as Dr. Hinde says, are also char- 
acteristic of Prioniodus abbreviatus. 

Fig. 5. Prioniodus hamatus, Bryant. 25. 
PRIONIODUS HAMATUS, Spec. Nov. 
Text fig. 5. Plate II, figs. 5, 6, 8, 11. 
Base narrow, slightly curved, and depressed at one end where 
it supports a large, robust and somewhat blunt tusk which is 
sometimes produced below the base. The outer margin of this 
tusk at its junction with the base usually bears a tubercule or 
short cusp. On the other side of the main tusk, the base carries 
four or five widely spaced denticles, variable in size and height. 
Base horn colored; teeth polished and tinted like ivory.» Conodont 
bed, Eighteen Mile Creek. 
PRIONIODUS ALATUS, HINDE 
Plate III, fig. 10; Plate IV, figs. 1-7. 
1879. Prioniodus alatus, G. J. Hinde, Quart. Journ. Geol. Soc., Vol. 
XXXV, p. 361; Plate XVI, fig. 5. 
This is a larger form than Prioniodus recedens, but equally 
variable in the expansion of the base and in the number of 
denticles thereon supported. The main tooth 1s large, triangular 
and compressed, one side gently rounded, the other, with a more 
or less pronounced ridge extending from the base nearly to the 
apex. One arm of the arched base carries a series of denticles. 
The teeth are creamy white; the base horn-colored or blackish. 
Underneath the main cusp is a lozenge-shaped cavity. From this 
a narrow groove extends the length of the base. 
