REPORT ON CORALS—HYDROCORALLIN &. 59 
conical tip (PL II. fig. 3,8). Just above the level of the top of the style is a circlet of 
small rough projections, which stand out from the wall of the gastropore and contract its 
bore at this point. 
Around the mouth of the gastropore is a circlet of from about ten to fourteen 
dactylopores, arranged symmetrically at equal distances from one another and from the 
centre of the mouth of the gastropore. The mouths of these pores are elongated towards 
the axis of the gastropore, so as to open into, and become continuous with, the cavity of 
this latter pore (Pl. HW. DZ, DZ). The openings of the dactylopores are continued down 
as wide slits, for some distance on the upper part of the wall of the gastropore, so that 
the pores have, as it were, two mouths placed at right angles to one another 
and confluent with one another, the one opening to the exterior, the other into the 
cavity of the gastropore. The cavity of each dactylopore consists of a wide upper 
chamber in the region of the widely open mouth (Pl. Il. TZ, TZ), and a narrow tubular 
continuation of this, which traverses the coenosteum in a direction parallel with that of 
the axis of the gastropore for about half the length of the latter. Against the outer 
wall of the pore is a small ridge-like excrescence, with an hirsute surface, which is 
the style of the dactylozooid (PI. IL. fig. 3, 8’), and which is described by Pourtalés as 
“a rudimentary septum in the shape ofa hairy fringe ” (Pourtaleés, .c., p. 34). 
The dactylopores in each cyclo-system are separated from one another by thin plates 
of calcareous matter which are directed inwards radially towards the axis of the gastropore 
(Pl. Il. fig. 3, P), and which at first sight have all the appearance of the septa of 
Hexactinian corals, and have hitherto been mistaken for such by observers. They are 
however, composed each of two thin Jaminze of dense calcareous matter, united by some- 
what less compact calcareous substance, which is freely perforated by canals for the 
passage of offsets of the ccenosarcal meshwork. The thin lamine are merely the 
juxtaposed walls of the adjacent dactylopores. These radially disposed plates, which 
may be termed pseudosepta, have their inner edges continued down the wall of the gas- 
tropore for a short distance beyond the margins of the mouths of the dactylopores as 
well-marked vertical ridges, which soon become merged in the general surface in their 
course (PI. IL. fig. 3). 
The cylindrical masses formed by each cyclo-system are sometimes flat, often gently 
rounded at the top. Their summits are irregularly circular in outline, but have an 
indented border, the indentations corresponding with the centres of the. pseudosepta 
in position, and representing the intervals between the opposed dactylopore walls, which 
are here not obliterated by growth of ccenenchym. ; 
The cyclo-systems, when viewed from above in a line looking directly into the 
mouths of the pores, show, in all essential particulars, the same structure as that which 
occurs in Allopora profunda, which is represented diagrammatically in Pl. IL. fig. 13. 
The styles of the tentacular zooids, 88, appear as small projections in the interspaces 
