REPORT ON CORALS—HYDROCORALLIN #. Cle 
in Anthozoans, than does the very curious simulation which exists in its ccenosteum. 
The resemblance is, however, in both instances merely superficial, and of no genetic 
significance. 
The branched and fringed processes of endoderm described as embracing the embryos 
in Hrrina and Stylaster appear to correspond with the similarly branched structures 
in Cordylophora lacustris, described and figured by Allman and F. E. Schulze.' 
I have described them as outgrowths of the spadix, but possibly the cup-shaped 
endodermal structure supporting the ova should not be so designated. 
The endoderm of the Stylasteride is always coloured, and seems most frequently 
to assume various shades of red or violet coloration, but in Astylus subviridis it is 
green. ‘The ccenosteum itself is in some species coloured, especially, it would appear, in 
Distichopora, but no doubt in many instances the coloration ascribed to the calcareous 
structures is in reality due to endoderm dried up within the interstices of the corallum. 
In a former paper I conjectured that possibly shallow water Stylasteridee might bear 
free gonophores, and perhaps medusiform ones, and that the occlusion of the gonophores 
within calcareous structures, and their adelocodonic condition, was due to the fact that 
the forms examined lived in the deep sea, This suggestion was in accordance with the 
observations of Allman, who has found fixed sporosacs in all deep-sea Hydroids 
examined by him.” I find, however, from specimens sent me by Count de Pourtaleés, 
that ampulle are especially well developed on the shallow water Stylaster roseus ; those 
in the female stocks being very large and prominent. There can, therefore, be little 
doubt that these structures occur throughout the family. 
In all the Stylasteridee in which the gastropores have styles, the gastrozooids must 
be protrusible in the expanded condition to a very slight extent. And the fact that in 
some genera the gastrozooids lose their tentacles seems to bear out this supposition. 
No doubt in active life the dactylozooids extend like long and filiform tentacles and 
‘atch and convey food to the gastrozooid, which nourishes them in return by means 
of its basal canals and the general circulation. It is to be noted that in those genera 
in which the gastrozooids have no tentacles, tentacles are wanting in the entire stock. 
The nariform and tubular projections of Hrrina are no doubt contrivances for 
extending the reach of the dactylozooids, whilst at the same time protecting them. 
In Acanthopora the bases of the dactylozooids are pushed out to a remarkable dis- 
tance from the gastropore mouths, and subsidiary dactylozooids of a smaller kind 
seem to be necessary to ensure the conveyance of food to the gastrozooid. G. O. Sars, 
who is the only naturalist who has observed a Stylasterid alive, never saw the zooids 
raise themselves above the level of the mouths of their cyclo-systems. 
1 F, E. Schulze, Uber den Bau und die Entwicklung von Cordylophora lacustris, Leipzig, W. Engelmann, 
1877, p. 34, plates iii, iv. 
* Allman, Gymnoblastic or Tubularian Hydroids, vol. ii. p. 155 ; Nature, Oct. 28, 1875, p. 556. 
