PRISTODONTID^. 
63 
Traquair, the resemblance of the dentition of Pristodug to that of 
the Plectognath Diodon is merely one of analogy, and does not 
imply the least affinity. 
Pristodas falcatoS) Davis. 
1862. Pristodus falcatus (Agassiz, MS.), Morris & Roberts, Quart. 
Joum. Geol. Soc. vol. xviii. p. 101 (name only). 
1883. Pristodus falcatus, J. W. Davis, Trans. Roy. Dublin Soc. [2] 
vol. i. p. 619, pi. bti. figs. 17-22. 
1884. Pristodus falcatus, J. W. Davis, Quart. Joum. Geol. Soc. vol. xl. 
p. 623, pi. xxvi. figs. 19, 20. 
1888. Pristodus falcatus, R. H. Traquair, Geol. Mag. [3] vol. v. p. 101. 
Type. Detached teeth ; British Museum. 
Coronal margin of upper tooth divided into a series of 10-18 
large, acutely-pointed denticulations, diminishing in size* from the 
centre laterally ; the centre of the margin is the line of division 
between the two largest denticulations, there being no median 
azygous apex. Coronal margin of the lower tooth smooth, with a 
series of minute pittings beneath, giving it the appearance of being 
finely denticulated, gradually rising from either side to a median 
acuminate, but not produced, apex. 
Form. ^ Loc. Upper Carboniferous Limestone : Yorkshire. 
36888 a, 49640-42. Four upper teeth ; Richmond. 
Purchased, 1862, 1878. 
P. 1442. Nine portions of similar teeth ; Richmond. Egerton Coll. 
P. 3015. Eighteen portions of similar teeth, some small ; Richmond. 
Enniskillen Coll. 
P. 4896-7. Five similar teeth ; Wensleydale. • Horne Coll. 
P. 3012-4. Two imperfect upper teeth, and impression of the pos- 
terior aspect of one lower, figured in Trans. Roy. Dublin 
Soc. [2] vol. i. pi. bci. figs. 20-22; Richmond. The 
original of fig. 21 is wrongly described as a lower tooth ; 
and fig. 20 does not represent the “ under surface ” of 
such a tooth, as stated in the text. Enniskillen Coll. 
P. 3016. Five upper and lower teeth ; Toredale. Enniskillen Coll. 
P. 1419. Four lower teeth ; Richmond. Egerton Coll. 
P. 3015 a. Twelve lower teeth ; Richmond. Enniskillen Coll. 
P. 4895. Two lower teeth ; Wensleydale. 
Horne Coll. 
