52 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Nov. 24, 
reefs and lagoons. The bathymetrical disposition of the species of 
the reefs has been studied with good results*; and it has become 
evident that there are natural-history provinces of Madreporaria, the 
most distinct being those of the Caribbean sea and the Indo-Pacific 
Ocean. 
Careful and systematic dredging in the Mediterranean, the North 
Sea, and the Atlantic has proved the existence of a deep-sea and 
abyssal, as well as of littoral coral faunas, which have nothing in 
common with true reef forms. The*anatomical construction of the 
majority of the deep-sea corals differs from that of the reef-builders 
and the species inhabiting shallows and lagoons in the neighbourhood 
of reefs. There are evident distinctions in the methods of growth 
and gemmation. The physical conditions of the areas are as diverse 
as the genera and species inhabiting them. 
The corals of the West Indies, Bermudas, Indo-Pacific, South 
Sea, China seas, and Red Sea, form one series ; and the species inha- 
biting the deep water and littoral tracts off some portions of the 
great continents are included in a second. The species of the first 
are infinitely more numerous than those of the second series, and 
there is no difficulty in distinguishing them. The external condi- 
tions which accompany both series are tolerably well understood ; 
and the instability of reef areas is comparable with the stability of 
the deep seas beyond their range. Recent researches have proved 
that vast districts of the deep-sea bottom are uncoralliferous, and 
that others maintain much coral life at immense depths f. 
Whilst the natural history of the existing Madreporaria has been 
carefully studied, the paleontology of the coralliferous strata has 
been by no means neglected. Monographs, properly illustrated, 
have described the fossil corals of certain districts; and systematic 
works have treated of the fossil Zoantharia as a whole. Reuss’s 
descriptions of the corals of the Oberburg in Styria, Castel Gomberto 
in the Vicentin, and Gosau in Austriat, are as exhaustive as the 
labours of d’Achiardi §, Seguenza ||, De Fromentel 4], and, last, but 
not least, of MM. Milne-Edwards and Jules Haime**. 
The description of the fossil corals of the Mesozoic and Cainozoic 
strata of Great Britain has been completedt+, and the relation of the 
successive coral faunas in them to those of the equivalent formations 
of the Continent has been studied and noticed. In fact, the litera- 
ture of the coral formations is sufficiently advanced for some gene- 
ralizations to be attempted between the peculiarities of the past and 
present faunas. 
* Michelotti and Duchassaing, Mem. dell’ Accad. Torino, 1865. Lyell, Prin- 
ciples of Geology, 1868. 
T Reports on deep-sea dredging (Proc. Roy. Soc. 1869), Carpenter, W. Thom- 
son, Gwyn Jeffreys. 
~ Essays in Wien. Akad. Denkschr. 
§ Coral. Foss. in Mem. della Soe. Ital. di Sci. Nat. 
|| Coral. Foss. in Mem. della Reale Accad. Torino, Serie ii. tomo xxi. p. 399. 
{| Polyp. Fossiles. 
** Pal. Soc. Brit. Foss. Corals. Hist. Nat. des Corall. 
+t Duncan, Pal. Soc. Brit. Foss. Corals. 
