Mr. H. J. Carter on Holasterella and Hemiasterella. 143 
with and attached to eacli other, so as in many specimens not 
only to obscure the form of the stellate, but to convert the 
whole into a solid mass. Hence it is only here and there that 
a comparatively complete form can be detached ; while the 
union of the rays of the different stellates, where in contact 
with each other, being without inflation or additional material 
at these points, leaves one in doubt as to how much, if not all, 
of this attachment may be due to the effect of fossillization, and 
that, in their original state, they were thus all separate. The 
cleavage, too, of the mineral being perpendicular to the long 
diameter of the ray and easily effected, causes, from their 
lamellar structure and extreme brittleness, the rays, where 
adherent to one another, even in the slightest degree, to yield 
to the force necessary to separate them without fracture, and 
thus defies all attempt to obtain a perfect spicule. Nor is it 
very clear what amount of central inflation originally existed 
in the spicules generally; for the accumulation of the fossilizing 
material having spread from these points especially, and, as 
already stated, the inflation which is chiefly evident in the 
smaller spicules (fig. 8) not keeping pace with the develop¬ 
ment of the lower arms, whereby the latter appear to be 
almost bodiless (that is, without central inflation, flg. 4), this 
also is not easily determined. 
Judging, however, from the entire want of fossilized fibre, 
like that which exists in the vitreous Hexactinellida, and, 
therefore, the Holorhaphidotic character of the aggregated 
stellates, it seems probable that they were not only originally 
ununited , but that the sponge did belong to the Holorhaphidota, 
in which order it might form a new group among the Sube- 
ritida, coming in provisionally after that of “ Laxa ” under 
the name of “ Holasterellina.” 
Again, the presence of the ovoid depressions (fig. 2, a a) 
sunk into the surface, which, leading to no outlets internally, 
could not be connected with the excretory canal-system, are 
almost identical in form with those to which I have alluded 
in my paper on the Parasites of Sponges under the head of 
“Crustacea” (‘Annals,’ 1878, vol. ii. p. 157), having been 
observed in the Holorhaphidota only (that is, not in any vitre¬ 
ous sponge), and especially in the Suberitida, where the head 
of the amphipod occupies the largest end of the ovoid pit. It 
is just possible for this reason also that these spicules were 
originally connected together by flaky sarcode, like that of the 
Suberitida of the present day, and thus Holorhaphidotic. Had 
I never noticed such depressions in the existing sponges with 
the crustaceans respectively in them, I should have been 
inclined to regard this as a peculiar character on the 
