HOLASTERELLA. 163 
the stellate spicules fill the interspaces between the rays of the larger; they also 
line the canals, and apparently cover the surface of the Sponge. 
Mr. Carter did not give a diagnosis of this genus apart from the characters of 
the typical species H. conferta. I have prepared that given above from a study of 
the type specimen described by Mr. Carter, and now in the possession of Mr. J. 
Thomson of Glasgow; and Mr. Carter kindly supplied me with some detached 
fragments from it. 
The type-specimen is in a very unfavorable condition of preservation, and the 
characters of many of its component spicules cannot be ascertained with certainty. 
The larger spicules are so fused and intermingled together that no complete forms 
are exposed.to view ; thereis no doubt, however, that some are normal hexactinellid 
spicules, with smooth, tapering rays, whilst others, judging from fragments, are 
peculiar forms with curved and spinous rays. The minute stellate spicules of the 
surface, and lining the canals of the Sponge, have from six to fifteen rays radiating 
from a thickened centre. It seems highly probable that the stellates with more 
than six rays may be merely modified hexactinellid spicules im which furcation has 
taken place in one or more of the normal rays. Owing to their small size, and their 
present condition, the central portion of these spicules is not clearly shown. 
The larger spicules, which Mr. Carter has described and figured as belonging to 
the type specimen, were not obtained from it, but they were detached spicules, and 
it is uncertain if they were derived from the same locality as the Sponge itself. 
Mr. Carter regarded these detached spicules (/. c., pl. xxi, figs. 4, 5, 7) as identical 
with those forming the interior portion of the skeleton of the Sponge, but after 
careful examination of the original specimen, I am unable to agree with this con- 
clusion. The larger spicules in it are to a large extent concealed and obliterated ; 
but, judging from the portions remaining, they appear to me to be quite distinct 
from the “double stelliform nail-like spicules,” originally figured by Mr. Carter as 
doubtfully belonging to Hyalonema Smithii (‘ Ann. and Mag. Nat. Hist.,’ ser. 5, 
Vol.d, p. 133, pl. ax, fig. 11). 
As this genus is, in part at least, composed of normal hexactinellid spicules, 
its systematic position appears to me to be in the Lyssakine group of the 
Hexactinellide. Mr. Carter, however, regards it as the type of a new group, 
‘ Holasterellina, among the Suberitida, thus belonging to his Holorhaphidota 
(= Monactinellidee). 
Only the typical species H. conferta can, in my opinion, properly be included 
in the genus; the other species which by Mr. Carter and myself (before that I had 
seen the original specimen) have been referred to it, | propose to place in distinct 
genera. 
