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JOURNAL OF THE GEOLOGICAL SOCIETY OF DUBLIN. 
edge of the valves, as exhibited in the impression under figure 5 b, which is 
about twice the natural size. 
This is not a rare species in the Tullyconnel limestone: it also occurs at 
Cultra, and in the neighbourhood of Manchester. In Durham, Germany, and 
Petchora-land, it is a characteristic Permian fossil. The genus belongs to the 
Carboniferous, Permian, Saliferous, and Jurassic Systems. 
7. Schizodus Schlotheimi = Cucullcea Schlotheimi, Geinitz. —PI. i., fig. 6; Mono¬ 
graph, pi. xv., figs. 31, (?) 32. 
This species, which was first described from specimens occurring in the 
Zechstein of Germany, belongs to an extinct genus closely related to Bronn’s 
Myophoria. Schizodus is equivalved, and possesses cardinal teeth arranged 
on the plan of those characteristic of Trigenia, but neither longitudinally 
grooved, nor so massive as in the last genus. It differs from Myophoria prin¬ 
cipally in the large tooth of the left valve being forked or bifurcated, like the 
corresponding tooth of Trigonia: in Bronn’s genus this tooth is massive. 
Schizodus, I suspect, characterizes the Carboniferous, Permian, and Saliferous 
Systems. Myophoria appears to have had a longer geo-chronological range, 
since it occurs in Devonian strata and the three succeeding systems,—some of 
the so-called Cucullseas (or Dolabras, M‘Coy) of the Marwood sandstone, 
(Upper Devonian) being of the genus. Goldfuss’s Megalodon truncatus , which 
I am disposed to consider as closely related to, or even identical with, Sowerby’s 
Cucullcea angusta , C. unilateralism and C. trapezium , is, I strongly suspect, 
a species of Myophoria. The Marwood fossils, it is said, are inequivalved; 
but I suspect this is only apparent, arising from distortion or unequal com¬ 
pression. 
Schizodus Schlotheimi is rather strongly inequilateral, a little tumid, 
rounded anteriorly, and somewhat tapering posteriorly, with an oblique trun¬ 
cation. All the specimens that have fallen into my hands are in the state of 
casts; I am therefore unable to speak of its external characters, except that 
the surface of the valves is nearly smooth, and marked on the anterior slope 
with a few faint wrinkles, impressions of which, owing to the thinness of the 
shell, are exhibited on the two specimens figured. An allied species, Schizodus 
truncatus , has occurred to me with marks of colouring still preserved—dark 
spots on a light ground, somewhat similar to the pattern exhibited on the 
recent Circe Castrensis. 
This is the species which I strongly suspect has given rise to the identifica¬ 
tions in Dr. Griffith’s list under the names Cucullcea unilateralism C. complanatam 
C. trapeziumm and C. Hardingii: fossils thus named are also noticed in 
M‘Coy’s “Synopsis of the Carboniferous Fossils of Ireland,” 1844, but without 
their localities being mentioned.* The only explanation I can give of these 
identifications is, that specimens of Schizodus Schlotheimi occur at Cultra so 
* In Mr. Kelly’s paper, previously referred to, these fossils are stated to be from 
Cultra. 
