fames on MontictiUfora. 3S9 
The Riigosa. The members of this, hke the previous group, 
are possessed of a stony corallum, and present generally both 
tabulae and septa. The order is divided into four families, 
Stauridce^ Cyathaxonida;^ Cyathophyllidce, and Cystiphyllidce. 
To the third of these belong Zaphrentis and Streptelasma^ but 
as none of the group seem related to the Montictdiporidce w^e 
pass on to the third and last order. 
The Alcyonaria. Of the five families into vs^hich this order 
is divided, but one presents any affinities to the monticuliporoids. 
This is the Heliopoi'idce Mosely. This author has examined 
Heliopora in a living state and describes it as having a well de- 
veloped, stony corallum, composed of corallites of two kinds. 
Both kinds are tubular; the larger ones are crossed by well de- 
veloped tabulce, and the walls are folded in such a wav as to 
give rise to a variable niunber of septa. The smaller, (inter- 
stitial?) tubes are destitute of septa, but have numerous tabulfe. 
The living parts of the corallum occupy only the spaces in the 
corallites above the uppermost septum. Several extinct genera, 
Heliobites^ Plasmopora^ &c., present similar features to Helio- 
pora and are referred to this family. Finally we find in the 
Mo7iticulipo}'idce several features which show it to be closely 
related to the Helioporidcr. In the sub-genera Dekayia, Co7i- 
stellaria and Fistulipora the large tubes are often nearly sur- 
rounded by smaller ones. In jMo7iticulipora proper, these 
interstitial corallites vary in number in different species, being 
sometimes very few, and again very numerous. Septa seem 
to be absent in both kinds of tubes, a point of difference from 
Helioporidce^ but tabulae are generally well developed in both 
kinds, though there is great variation in this respect. In certain 
species of Monticulipora it is found that the walls of the coral- 
lites are more or less inflected, and it may be that these are the 
possible remains of former septa. From this examination it is 
clear that the Alonticuliporldcc are in many features similar to 
the Helioporidce', and it would seem the best plan to place the 
families side by side, as members of the Alcyonaria. 
If we turn now to the Folyzoa we find here also a mixed as- 
semblage of forms. The class is divided into three sections, all 
of which are in general terms characterized uj^on the living 
animal. The first two sections contain three genera, all of 
