28 
ICHTHTOTOMI. 
Genus DICRENODUS, llomanowsky 
[Bull. Soc. Imp. Nat. Moseou, vol. xxvi. no. 1, 1853, p. 407.] 
Syn. Carcharopsis, L. Agassiz, Poiss. Foss. vol. iii. 1843, p. 313 (unde- 
fined) ; J. W. Davis, Trans. Koy. Dublin Soc. [2] vol. i. 1883, 
p. 381. 
Pristieladudui, F. McCoy, Brit. Palseoz. Foss. 1856, p. 642. 
Crown of tooth relatively large, thick, and conical, but much 
compressed, with the two cutting-edges coarsely denticulated ; 
lateral cones absent, or not more than two on each side. Base 
expanded at right angles to the crown posteriorly, thick, subsemi- 
circular in shape. 
Both the specimens to which Agassiz gave the name of Carcha- 
ropsis being contained in the Enniskillen Collection and mentioned 
below, it can bo determined definitely that they are geuerically 
identical with the teeth described by llomanowsky as Dicrenodus 
and by McCoy as Prist ieladodus. The present writer has seen no 
evidence of the difference in the form of the root remarked upon 
by J. W. Davis, loc. cit. 
Dicrenodus dentatus (McCoy). 
1843. Carcharopsis prototypns, L. Agassiz, Poiss. Foss. vol. iii. p. 313 
(name only). 
1866. Pristicladodus dentatus, F. McCoy, Brit. Palssoz. Foss. p. 042, 
pi. 3 G. fig. 2. 
1883. Pristicladodus dentatus, J. W. Davis, Trans. Roy. Dublin Soc. 
[2] voL i. p. 384, pi. xlix. fig. 22. 
1883. Carcharopsis colei, J. W. Davis, Trans. Roy. Dublin Soc. [2] 
vol. i. p. 383, pi. xlix. fig. 2G. 
1884. Pristicladodus dentatus, J. W. Davis, Quart. Journ. Geol. Soc. 
vol. xl. p. 020, pi. xxvii. fig. 4. 
1888. P-isticladodus dentatus, R. II. Traquair, Geol. Ma‘>'. [3] vol. v. 
p. 103. 
Type. Detached tooth. 
Denticulations of coronal margin large, well-defined, abruptly 
truncated ; no lateral cones. 
Form. ^ Loc. Lower Carboniferous Limestone: Armagh, Ireland. 
Upper Carboniferous Limestone: Ayrshire, Scotland; Yorkshire, 
Derbyshire, England. 
46044 . Imperfect tooth ; Bcith, Ayrshire. 
Presented by Itohert Craig, Esq., 1874. 
* The identity of this genua with Chilodus, Giobel (Fauna Vorw. vol. i. 1847, 
p. 352), asserted by Giebel and Heiutz (Zeitschr. gesammt. Katurw. 1854, p. 77), 
must be regarded as very doubtful. 
