112 
MR. H. N. MOSELEY ON THE 
The large canals in the stem of Sarcophyton , which are in reality long drawn-out 
prolongations of the body-cavities of the polyps, may be considered to correspond to 
Kollikee’s “sinus;” the vertical and transverse canal-systems to the “ canales nutrici 
majores ; ” the network in connexion more directly with the vertical system to the “ vasa 
nutrica minora.” Apparently there are no vessels corresponding to the “ vasa capillaria,” 
their place being occupied by the network formed by the small ramified corpuscles in 
the sarcosome. 
The transverse and vertical canal-systems anastomose with one another frequently, 
but only here and there. Occasionally, but rarely, the canals from the bottoms of the 
zooid-cavities join directly the transverse canals. The canals have a wall of fibrous 
tissue directly continuous with the fibrous layers of the zooid- and polyp-cavities, and 
are lined internally by entodermic cells, Plate 9. fig. 9, C. Sac-like enlargements or 
swellings are constantly to be seen on the canals of Sarcophyton, both near the surface 
and in the deep tissue. In one such swelling was found a parasitical cyst of oval form 
and with greenish contents ; its nature could not be determined. The polyps in Sarco- 
phyton are so disposed that they have the dorsal intermesenterial spaces directed towards 
the centre of the pileus, and at the verge of the pileus these spaces uppermost. At 
least this disposition was observed to hold good in three opposed radial directions from 
the centre of the pileus. A whole specimen was not available for examination. 
As in Heliopora the polyps are not disposed with perfect regularity in this manner, 
so that radial lines from the centre of the pileus would pass directly through their 
longer diameters. Many of them are rotated more or less on their axes, so as to be 
inclined to the radial lines. They are most regular in disposition at the margin of 
the pileus. The zooids, though preserving a general uniformity of arrangement, which 
proves their single pair of mesenterial filaments to be the dorsal ones, are still more 
irregular in disposition. 
Notes on the Structure of two Species of Millepora. 
I have examined the structure of two species of Millepora ; one, Millepora alcicornis, 
was obtained at Bermuda, the other species was found at Zamboangan, Mindanao, 
Philippine Islands. The investigation of the structure of the genus Millepora is beset 
with unusual difficulties. The calcareous tissue of the coral is very hard and compact, 
and the soft tissue, on the other hand, very soft and very much altered and shrunk by 
the action of spirit. Further, the polyps are extremely small. I give here only a few 
results at which I have arrived from the examination of the material which I have at 
present at command. I hope to obtain abundance of Milleporae at Hawai and Tahiti, 
and to make a thorough investigation of their structure. 
The corallum of Millepora , although in its histological structure it resembles Helio- 
pora very closely, being formed of a similar fibro-lamellar tissue, differs extremely from 
Heliopora in the coarse arrangement of its components. Instead of being composed of a 
series of parallel tubes divided by tabulae, the corallum of Millepora is composed of a net- 
