110 
ME. H. N. MOSELEY ON THE 
and the zooid-cavities contract. There are narrow intervals between the circular areas, 
in which there project the thickly set tips of spicules showing through the epidermis 
(Plate 9. fig. 9) and forming stiff supports to the walls of the cavities. 
The structure and relations of the zooids and polyps are seen in Plate 8. fig. 1. 
The polyps present no remarkable features ; they have numerous fine spicules in their 
antennae, which are, as is usual, simply retracted, and are provided with protractor and 
retractor muscles. Of the protractor muscles (P M in fig. 2) part of the fibres appear 
to be inserted into the wall of the polyp-cavity, whilst others are continued on the 
inner borders of the mesenteries. 
The muscles are arranged with regard to the septa as in Heliopora , Pennatulids, 
and TJmbellula , showing a dorsal and ventral intermesenterial space; and here the 
protractor muscles were seen to he placed on the opposite sides of the mesenterial 
plates to the retractors. Two mesenterial filaments are longer than the rest ; probably 
they are those of the “Dorsalfach,” since the only two retained by the zooids are the 
dorsal ones. The ova are developed deep down in the polyp-cavities ; they have 
the usual form of the ova of Alcyonarians. They measure, when mature, about 
7 millims. in diameter. They are placed in Plate 8. fig. 2 at a greater height up in 
the cavity of the polyp than that at which they usually occur. Ova are to be found 
in the tubular prolongations of the polyp-cavities very deep in the colony. 
The polyp-cavities widen out beneath the surface to contain the polyps and gradually 
contract again below ; they have an extreme diameter of about 2 millims. against a 
diameter of about ‘35 millim., which is that of the tubular cavities of the zooids. The 
zooid-cavities are only about one fifth the length of the polyp-cavities. The zooid- 
cavities contract below, and their tubes gradually narrowing join the canal-system, as 
is described by Kolliker to be the case in Sarcojpliyllum (Kolliker, l. c. l te Abth. Taf. 
viii. fig. 68). The zooids (Plate 9. fig. 9) consist of a simple globular stomach lined 
within by a thick epithelium, a prolongation of the ectoderm, and communicating 
with the exterior by a narrow tubular mouth ; they have no trace of tentacles. The 
inner surface of the stomach is covered with long cilia, directed downwards and 
inwards. Near the surface of the body, just beneath the ectoderm, eight mesenteries 
are present in all the zooids ; but four of these extend to a much less depth than the 
others, and hence in a horizontal section at a very slight depth from the surface all the 
zooids in section are seen with only four mesenteries. The four deeper mesenteries 
are those attached to the ends of the long axes of the stomach, i. e. the dorsal and 
ventral. Only two mesenterial filaments are developed in the zooids, and these are 
those of the dorsal mesenteries. The filaments are attached throughout their length 
to the margins of the septa. The zooids are without sexual organs. The body is 
covered with an ectoderm resembling in structure that of Heliojpora ; but it was not 
sufficiently well preserved in the available specimen to show its exact structure. No 
thread-cells were found in the Sarcojphyton. The mesoderm forms a sarcosome 
consisting of tongh, gelatinous, transparent connective-tissue, in which are distributed, 
