40 
DEVONIAN FAUNA. 
although the hinge cannot be seen, its general similarity to Macrodon Hirsonensis, 
Lycett, and still more to numerous species of Parallelodon described by de 
Koninck from the Carboniferous of Belgium, leaves little doubt that it belongs to 
the latter genus. 
Affimties. — In Area Miehelini, d'Archiac and de Verneuil,^ the nmbo is less 
anterior, the posterior side shorter, and the inferior margin straighter and less 
oblique. 
Area prisca, Goldfuss,^ has a more decided median depression on the back. 
8anguinolites timidus, Phillips,^ sp., as given by de Koninck* is almost exactly the 
same shape, but is less transverse, and has a smaller umbo and a broader hind wing. 
The present form is much more transverse than any of the Carboniferous 
species described by de Koninck except P. tenuis, de Koninck,^ which has a 
much shorter hinge-line ; and P. meridionalis, de Koninck,^ which has a much 
less regular ornament and a less prominent beak. 
2. SuB-oiiDEK.-HBTEEOMYARIA, Zi^feZ, 1881. 
I. Family. — PRASiNiDiE, Stoliczha, 1871. 
1. Genus.— MomoLOvsm, Hall, 1847. 
These shells are elongate, edentulous, transverse, subovoid, with proximate 
anterior subterminal beaks, more or less straight upper margins, and large 
anterior muscle- marks. They occur in the Silurian and Devonian. 
The genus or sub-genus Modioviorpha, Hall, 1870, is chiefly differentiated 
from the present by the possession of a single strong tooth. Beushausen and 
Barrois are inclined to refer to it the Devonian species described as Modyiolojjsis. 
As the binge is not shown in either of the species described below, it is 
impossible to decide this point with regard to them. 
1 1842, d'Archiac and de Verneuil, ' Greol. Trans.,' ser. 2, vol. vi, pt. 2, p. 373, pi. xxxvi, fig. 6. 
1832-40, Goldfuss, 'Petref. Germ.,' vol. ii, p. 282, pi. cl, fig. 10. 
3 1836, Phillips, ' Geol. Torks.,' vol. ii, p. 209, pi. v, fig. 3. 
1885, de Koninck, 'Ann. Mus. Eoy. H. N. Belg.,' vol. ix, pt. v, p. 81, pi. xvi, fig. 6. 
5 Ibid., p. 148, pi. xxiv, fig. 25. 
* Ibid., p. 158, pi. xxvi, fig. 6. 
