Millepora and Stromatopora. 305 
lary system of blood-vessels in the warm-blooded animals), 
proceeds from central points, and thus resembles the stelliform 
arrangement characteristic of Stromatopora. 
That this stelliform arrangement should not have been 
exactly the same even in the different species of Stromatopora 
is as certain as that in all it seems to have been connected 
with the same function, and that function to have been what 
has been above stated. But let us now tur for a few 
moments to the able observations of Mr. H. Moseley, who has 
studied the Milleporide in their living state (Phil. Trans. 
1876, vol. 166, p. 91). 
Mr. Moseley states that specimens of Helioporacerulea, 
which were obtained at Zamboangan, in Mindanao, one of the 
Philippine Islands, and Millepora alcicornis, in “ great profu- 
sion” at Bermuda, were found to be as different in their 
minute structure as in their general form; for while the 
corallum of Heliopora cerulea was observed to consist of 
“tubes of circular section, of nearly uniform diameter, closely 
packed side by side. . . . with their walls, where touching, fused 
together,” and the intervals filled up by a hard tissue, which 
appears above the margins of the tubes “in papilliform pro- 
minences”” (/.c. p. 99), that of Midllepora alcicornis was 
found to be composed of a network of tortuous branches of 
hard tissue, in which “the soft tissues appear to occupy a 
series of tortuous canals,” “ that lead from the calicles in all 
directions, and, anastomosing freely with one another, join the 
cavities of the surrounding calicles”’ (/. c. p. 113)—to which, 
as before stated, might be added that the tubes of the calicles 
are imbedded in this tissue at variable distances from each 
other respectively, as further indicated by the distance between 
these apertures on the surface. 
Mcreover Mr. Moseley describes our ‘ grooved venation ”’ 
as ‘‘canal-systems,” the tubes of which are “ not only lined 
by, but also always more or less filled with entodermic cells.” 
They are divided into two systems, viz. a deep or horizontal 
and a superficial or more or less vertical system—the former 
being that which I have more particularly described in Mille- 
pora alcicornis, and whose canals, cut across in the vertical 
section of this species, may be seen just below the last-formed 
or external layer in the same position as that figured by Mr. 
Moseley in Heliopora (l.c. p. 105, pl. viii. fig. 1, V', and 
pl. ix. fig. 8). That this is not a water-vascular system is 
thus proved beyond a doubt, as clearly as that it is the grooved 
venation, in which the original soft tube may be seen, as first 
noticed in Hydractinva echinata (‘ Annals,’ 1877, vol. xix. 
