MIDDLE AND WESTERN ENGLAND AND SOUTH WALES. 363 
Monrtirvatrra srmpiex, Duncan, Suppl. Brit. Foss. Cor. pt. iv. p. 9, 
pl. iii. figs. 16-17. 
A single example of this coral, consisting of a polished section 
imbedded in the stone, which was taken by me from the Brocastle 
coral deposit, presents exactly the same peculiarities which are 
shown in Prof. Duncan’s figure 17. I wish, however, to remark 
that the much elongated form of the calice, and the angle observable 
in some of the septa, are merely the result of pressure. I have ob- 
served the same thing in some other species. 
Montitvattrs Watt, Duncan, loc. cit. p. 7, pl. vill. figs. 5, 
6, & 7. 
Prof. Duncan remarks of this species that there is a double wall 
in some places, and that the rudimentary septa “‘ which are barely 
visible in the true calice are distinct in the outer rim.” He might 
further have noted the continuity of the older septa from the outer 
rim, through the inner wall in the calice proper. This is well shown 
in Prof. Duncan’s figure, and is a good illustration of rejuvenesence. 
The habitat is Brocastle. 
MonrLivaLitra RHZTICA, Tomes, Quart. Journ. Geol. Soc. vol. xxxiv. 
p- 180. 
This species, as I have already stated in my original description, 
is characterized by a very thin discoid form, and by the great size 
and relative prominence of its primary septa. 
MonTLIVALTIA, sp. 
A young and imperfectly preserved specimen of a species of Mont- 
livaltia, which was parasitic on a Modiola, was found by me in the 
black shales of the Rhetic formation during the construction of the 
Penarth Docks in 1860. Although I am able to state definitely 
that it was found low down in that formation, I cannot fix its pre- 
cise position further than to say that it occurred at no great distance 
either above or below the bone-bed. It is included here because I 
believe it to be the most ancient representative of the genus which 
has been met with in this country. 
Genus THEcosmin1a, Edw. & Haime. 
Of the species appertaining to this genus which come within the 
scope of the present paper, some have been said to increase by gem- 
mation, and others by fissiparity. And there are a certain number 
which, like the St. Cassian species, have a great many septa, 
and others, again,1in which the number of septais verysmall. The 
latter would seem to have a more truly Liassic affinity than the 
others. Those which have very short and stunted forms, and more 
especially such as increase by gemmation, are possibly only the 
peduncular portions of species which, in their ultimate growth, con- 
stitute genera quite distinct from the present. They might readily, 
except for their well-developed epitheca, bear some relationship to 
