]7G 
StLACniI. 
1884. IHeurodus looudi, J. W. Davis, Quart. Journ. Geol. Soc. vol. xl. 
p. 024, pi. xxvii. figs. 14-17. 
1880. rieurodtts woodi, J. \V. Davis, Geol. Mag. [3] vol. iii. p. loG- 
Type. Detached dental plates; Heed Collection, York Museum. 
Axial Carina of the dental crown narrow, rounded, divided by 
transverse sulci, corresponding to the divisions between the incom- 
pletely coalesced components ; lateral notches very deep. 
The dental plates of this species were first described by W. J. 
llarkas, but were not figured until 1883, when J. W. Davis iiroposed 
the name by which the species is now known. 
Form. 4' Toe. Ujipcr Carboniferous Limestone : Yorkshire and 
Derbyshire. 
P. 4887. Eight dental plates ; Yoredale Hocks, Wensleydale, York- 
shire. Hovue Coll. 
P. 5357. An abraded dental plate, probably referable to this species ; 
Ticknall, near Melbourne, 8. Derbyshire. Wilson Coll. 
Dental plates of a species of PleuropUuv, from the Lower Car- 
boniferous Limestone of Belgium, have been described under the 
name of Tomodus lacimcUiis, L. G. de Koninck, Eaune Calc. Carbf. 
Bolg. pt. i. (1878), p. 61, pi. vi. fig. 20. 
Genus PSEPHODUS, Agassiz. 
[Morris and Hoberts («.u Agassiz, M8.), Quart. Journ. Geol. Soc. 
vol. xviii. 1862, p. 101 '.] 
Syri. llelodus, L. Agassiz, Poiss. Foss. vol. iii. 18.38, p. 104 (iu part). 
Ltyphodus, II. Homanowsky, Bull. Soc. Imp. Nat. Moscou, vol. 
xxxvii. pt. ii. 1864, p. 1(10. 
Aspidodus, Newberry & Worthen, Pal. Illinois, vol. ii. 1866, 
p. 92. 
T<eniodus,Sit. John & Worthen, I’al. Illinois, vol. vii. 1883, p. 75 
(•n part). 
At least one series of the teeth upon each ramus of the jaw repre- 
sented by a large gently curved plate, quadrangular, without coronal 
ridges or any marked iurolmont of the outer border, and having at 
least the antero-lateral and postero-latoral margins of the crown 
Xbe name only ig here mentioned and applied to tlie species previously 
described and figured by M'Coy and Portlock under the name of Cochliodas 
nwynm. The type species being thus already well-defined in 1802, the generic 
name is generally regarded as dating from that year. 
