REPORT ON CORALS—HELIOPORID. 125 
more marked, and the corallum appears as if formed of a series of calicles fitted one 
within another. The discovery by Mr Charles Stewart’ of the existence in Tubipora 
musica of infundibuliform tabule, which form delicate axial tubes within the larger 
tubes of the corallum just as in Syringopora, seems to prove undoubtedly that Dana, 
Haeckel, Zittel, and others are quite correct in placing these fossil forms in near relation 
with Zubipora. Professor Alleyne Nicholson,’ who disagrees with the conclusions of 
the above-named authors, and considers Syriigopora to be allied to the Zoantharia 
perforata, is apparently unaware of Mr Stewart’s observations. He gives some account 
of the genus Syringolites (Hinde) which, though it has polygonal contiguous coralites, 
with mural pores like Favosites, has also infundibuliform tabule, and even axial 
tubes like Syringopora. This link closely connecting Favosites and Tubipora through 
Syringopora is a further proof of the Alcyonarian aflinities of Favosites and its 
other allies. 
On the Septa of Heliopora.—aA difficulty appears to arise from the peculiar mode of 
the development of the calicles by budding in Helvopora, the foldings of the walls of the 
calicles being due, to a considerable extent at least, to the formation of these walls from 
a circle of ccenenchymal tubes. The septa are, however, not entirely formed in-this way. 
It would of course be of great interest to see whether the primitive calicle, in the develop- 
ine Heliopora colony, forms calcareous septa. 
Heliopora having so commonly twelve septa, and in conjunction with these eight 
mesenteries, it was at first thought that here some key would be found to the elucidation 
of the question of the relations of the tetrameral corals to the Hexactimians; but no 
definite arrangement of the eight mesenteries to the twelve septa could be discovered. 
Zooids of Sarcophyton compared with those of Pennatulids.—With regard to Sarco- 
phyton, the fact that its colonies are composed of multitudes of siphonozooids, combined 
with a lesser number of sexual autozooids, as amongst the Pennatulide, was discovered 
by Kolliker, who failed to find such a condition existing in any other member of the 
Aleyonide or Gorgonide. In Sarcophyton and in Heliopora the “ Dorsalfaicher” 
are all turned towards the axes of the colonies and directed upwards, just as in 
Pennatulide. The siphonozooids in their structure seem to conform very closely to 
those of Pennatulids (Sarcophyllum, e.g.); but to the list of distinctive differences 
between the siphonozooids and autozooids of Pennatulids given by Kolliker, viz., the 
absence in the siphonozooids of tentacles, the presence of two mesenterial filaments (the 
dorsal ones), the absence of generative organs, and the shortening of the Hypogastric 
region to such an extent that it fuses with the anastomosing canal system—to these 
marks of distinction must be added, in the case of the siphonozooids of Sarcophyton, the 
fact that four of the mesenteries, the dorsal and ventral pairs, are deeper than the others. 
1 ©, Stewart, F.L.S., On a New Species of Stylaster, with a Note on Tubipora, Jour. of the Micro. Sei., 1879. 
» H. Alleyne Nicholson, l.c., pp. 18, 19, 214. 
