56 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Nov. 24, 
ramed, is often dredged up off Madeira, and in deep water off Cadiz. 
A second species is found in the Gulf of Gascony. 
Amphihelia oculata, Linneeus, is found at great depths in the 
Mediterranean Sea and in the Atlantic south of the Faroe Islands ; 
and there is a species in the Australian seas. Canocyathus and Cla- 
docora haye species amongst the deep-sea Mediterranean forms; and 
a species of this last genus is found off Madeira. 
There are some genera which are characterized by a budding from 
an expansion of the base of the coral, or which throw out stolons. 
Astrangia astreiformis is a type of this family ; and it is a moderately 
deep-water species off the eastern coast of the United States, north 
of the reef area. 
Another form, Cylicia tenella, Dana, occurs in deep water off the 
south-eastern coast of Africa, and also near Australia; and allied 
species are found off the New-Zealand and Australian coasts. 
There is a facies peculiar to these compound deep-sea corals, 
produced by their method of budding and growth, and by the 
absence of cellular coenenchyma. When a collection of them is 
placed by the side of a series of specimens of reef-making corals, the 
distinction is very evident. 
The habitats of these deep-sea species are rarely, if ever, invaded 
by the true reef forms*. 
Ill. Exceptions. 
There are deep-sea species of the genus Stylaster, Gray, (Allopora, 
Dana). Thus, Stylaster flabelliformis, Lamarck, sp., was found at a 
depth of 160 fathoms off the Isle de Bourbon. A closely allied spe- 
cies lives in deep water off the coast of Norway. These corals often 
have a coenenchyma uniting the buds; but it is of the dense non- 
cellular structure which peculiarizes the family of the Oculinide, and 
not of the lax tissue which, with one exception, is seen in the ordi- 
nary reef corals. 
The genus Madracis, which has deep-sea species off the Isle de 
Bourbon and Madeira, is an exception also; but the explanation just 
given suits its case. 
LY. Lirrorat CoRats BELONGING To THE DErp-sha Cora Fauna. 
Corals are occasionally found between low spring-tide mark and 
five fathoms, on the coasts of continents and large islands. Perfectly 
pure sea-water, freedom from muddy sediment and fresh water, a 
rocky bottom, and tolerably deep water close by appear necessary 
for their existence ; and as these conditions are not to be found every- 
where, the littoral corals are scarce. Vast tracts of the deep sea 
may be tolerably coralliferoas, yet the nearest coasts are sparsely 
tenanted by a stunted coral fauna. 
Considering the evidence which has been accumulating for years 
respecting the abundance of deep-sea Madreporaria in some parts of 
the Mediterranean and the Western seas of Europe already men- 
* Count de Pourtales, Bull. Mus. Harvard Coll. nos.6 and 7. The S¢ylasteres, 
Errine, Crypthelie, Haplophyllie, and Thecopsammie, &c. described by him are 
deep-sea dwellers in and near a reef area. 
