562 
DE. CAEPENTEE’S EESEAECHES OX THE FOEArMEXITEEA. 
zoophyte, like the Acervulina acinosa of Schultze, but -with more of the compactness of 
Polytrema miniacea. 
219. I now return to the form of Tinoporus on which the genus was originally esta- 
blished, the T. haculatus of Moxtfoet ; which agrees closely with T. Icevis in the 
fundamental characters of its organization, but differs in being furnished with a variable 
number of radiating appendages that give it a strong resemblance to Calcanna. Of the 
specimens in my possession, the greater part present the aspect represented in Plate 
XVIII. figs. 2, 3, 4, 5, and on a larger scale in fig. 6 ; and these were collected from 
coral reefs in various parts of the Polynesian Archipelago, — my earliest acquisition of 
them, however, having been from the contents of the stomach of an Echinus taken on 
the coast of Borneo, which were kindly put into my hands by Dr. J. E. Gray. I am 
informed by Mr. Denis Macdonald that on certain coral islands which he has par- 
ticularly examined, these organisms are so extraordinarily abundant, that they accumulate 
in the lagoons in regular strata, commonly alternating with strata of Orhitolites. The 
more massive and ruder forms represented in Plate XVIII. figs. 7, 8, 9, 10, occur' in 
Mr. Cuming’s Philippine collection. 
220. External Characters. — The typical form of the central portion of T. haculatus 
(Plate XVIII. figs. 2-6, and in section in Plate XXI. fig. 7) may be considered as an 
oblate spheroid; sometimes, however, it is nearly spherical, and sometimes it is much 
flattened out, especially when the body extends itself into the radial prolongations, as 
in Plate XVIII. fig. 4. Its surface is divided into areolse (fig. 6) very mueh as in 
T. Iwvis', but the angles of junction of the partitions between the areolte are very 
commonly occupied by rounded projecting tubercles, strongly resembling those of 
Calcarina. The number and size of these tubercles vary greatly among different 
individuals, as will be seen on comparing figs. 2 and 4, Plate XVIII*. From the 
marginal portion of the central disk there spiing a variable number of conical pro- 
longations having the furrowed surface of those of Calcarina', and these appear seated 
(so to speak) upon extensions of the central disk itself, which is sometimes so deeply 
subdivided at its margin as to resemble the body of a Star-fish (Plate XVIII. figs. 4 
and 7), the areolar division being continued nearly to the extremity of each ray, and its 
point only being formed by the furrowed prolongation. These appendages are usually 
from 4 to 6 in number ; I have occasionally seen only 2, and in no case have I met with 
more than 8. They usually diverge in or near the equatorial plane ; but they some- 
times come off in very different directions (Plate XVIII. figs. 8, 10). 
221. Internal Structure. — The general organization of T. haculatus, brought into Gew 
by sections taken in different directions, does not differ in any essential respect from 
that of T. Icevis ; the origin of the whole aggregation of chambers in a central cell, their 
subsequent multiplication both horizontally and vertically, and their methods of com- 
munication in both directions, being all the same. As akeady mentioned, I have very 
* They seem to be altogether wanting in the Philippine specimens, being apparently replaced by a 
multitude of small spines, which give to their siu'face a hispid aspect. 
