STKTJCTUEE AND RELATIONS OE CERTAIN CORALS'. 
117 
in the ‘ Proceedings’ of one of the learned societies of Vienna — I think in the ‘ Sitzungs- 
berichte.’ 
A remarkable fact is that the parasites are distinctly green, though they appear to 
be fungi, and those of shells are described as fungi. Possibly the parasites in question 
have already been described by Professor Kolliker. I have, of course, not access to 
his paper*. 
[Postscript. — Received November 25, 1875. 
August 11, 1875, Honolulu. 
Since writing as above and since sending off my paper to the Royal Society, I have 
come upon a passage in the ‘Voyage autour du Monde de 1’ Astrolabe : Zoologie,’ Quoy 
et Gaimard, vol. iv. Zoophytes, pp. 252, 258 (Paris, 1832), which is to the following 
effect : — 
M. de Blainville’s observations on the animal of Heliopora ccerulea led him to 
remove it from the genus Pocillopora, in which it had before been placed, and form 
the genus Heliopora for it, because the Pocilloporce have never more or less than 
twelve tentacles. 
Heliojpora has either 15 or 16 short, broad, triangular, pointed tentacles, forming a disk 
around the mouth. The animals were made out with difficulty with a powerful lens. 
(Eight compound tentacles have evidently been mistaken for sixteen simple ones.) 
Formerly Quoy and Gaimard mistook, on the voyage of the ‘ Uranie,’ the expanded 
parasitic Leucodoras for the polyps of Heliopora. They call them small parasitical 
zoophytes, probably of the class of Annelids. 
At p. 245, Quoy and Gaimard describe the twelve short tentacles of Pocillopora dami- 
cornis. The nature of the polyps of Pocillopora was therefore well known long before 
Prof. Verrill’s examination of themf.] 
CONCLUSIONS. 
Heliopora is most undoubtedly an Alcyonarian. The number of its mesenteries, and 
the distribution Avith regard to them of the retractor muscles, the form and number of 
its tentacles, are decisive evidence in the matter; and this evidence is borne out by 
almost every item of histological structure. In the peculiar manner in which the re- 
traction of the tentacles takes place, viz. by introversion, Heliopora seems to differ from 
* Since the above was written I have found the same parasites in various corals from all parts of the world. 
t Received Eebruary 28, 1876.— In the nurse-stocks of several species of Fungia a kind of intracali- 
cinal gemmation appears to take place. On the separation of a young free Fungia from the nurse-stock, 
the next free Fungia buds out from the centre of the scar left on the stem, i. e. from what has once been 
the centre of the calicle of the stock. (See Semper, Grenerationswechsel hei Steinkorallen.) I have lately 
found a very fine specimen of the nurse-stocks of a large species of Fungia at Tahiti, and have been able 
to see this fact quite plainly. It is owing to this mod.e of growth that the stems of the nurse-stock 
become jointed. 
R 2 
