312 
DEVONIAN FAUNA. 
figures, if it belongs to the same species as the other, represents a variety which I 
have not met with among the English specimens. 
Prof. F. Romer^ appears to have been the first to point the extreme variability 
of the present shell. After the examination of a large number of examples he 
united the M. hitineata, M. intermedia, M. coronata, and M. bigranulosa, as well as 
more doubtfully the M. hinodosa, and M. angulata, of Groldfuss and of d'Archiac 
and de Yerneuil. 
De Koninck, in his earlier work, figured a fiDSsil from the Carboniferous of 
Belgium under the name of M. Verneuiliana,^ which he identified with M. angulata, 
d'Arch. and de Verneuil, but separated from M. angulata, Phillips. This seems 
exactly similar to some specimens of the present shell, which in that case would 
have to be regarded as reaching into the Carboniferous. In his later work,* 
however, de Koninck retracts his identification ; and in the enlarged figure, which 
he there gives, the minor ornament is very different, and, therefore, at least as 
amended, his species is distinct. M. angulata, de Koninck,* though identified by 
him with Phillips' Devonian shell, and Pleurotomaria angulata, de Koninck,^ are 
two totally different species. There are, however, numerous specimens labelled 
M. angulata and M. Verneuiliana in the British Museum from the Mid. Dev. of 
Petigny, Belgium, which while they agree with our var. angulata, PI. XXX, 
figs. 8 — 10, vary very little, and show that in Belgium at all events it is a fixed 
variety, if not even an established species. 
I have not found any specimens agreeing with M. hitineata, d'Archiac and 
de Verneuil, among the English shells. It appears, however, to come very close to 
one of the figures of his M. intermedia and to lie between our groups intermedia 
and angulata, differing from the first in having no tubercles, and from the latter in 
having less angulated whorls. I think that it most probably belongs to the same 
species. It certainly has a somewhat distinct appearance owing to the breadth of 
its whorls, but it may in this respect be compared with the specimen figured at 
PI. XXIX, fig. 8. M. hilineata, Sandberger,^ is a different shell, with evenly convex 
whorls and a low sinus-band, and probably belongs to M. loxonemoides, n. sp. ; 
Goldfuss figures three specimens under the name of M. hilineata which bridge over 
the difference between d'Archiac and de Verneuil's figure and some of our specimens 
(e. g. PI. XXX, figs. 8 and 12) ; and a number of foreign specimens are in the 
British Museum by which a perfect chain can be arranged from even more 
aberrant specimens than that figured by d'Archiac and de Verneuil, and the 
ordinary nodulated varieties of the shell. 
1 1844, F. Eomer, ' Rhein. Uebergangsgeb.,' p. 80. 
2 1842-44, de Koninck, ' Desc. Anim. Foss.,' p. 414, pi. xsxviii, figs. 5 a, I. 
2 1883, de Koninck, ' Ann. Mus. Roy. H. N. Belg.,' vol. viii, pt, 4, p. 25, pi. xxxiv, figs. 35 — 37. 
* 1842-44, de Koninck, 'Desc. Anim. Foss.,' p. 412, pi. xxxviii, figs. 8 a — c. 
^ Ibid., p. 369, pi. xxsvii, figs. 2 a — e. 
6 1853, Sandberger, ' Verst. Rhein. Nassau,' p. 204, pi, xxiv, fig. 17. 
