62 Canadian Record of Science. 
through the unequal development or even suppression of 
one or more of the individual rays, so that spicules with 
five, four, three, or merely two rays only, are frequently 
present, and in the same species of sponge several modified 
forms of spicules may be found. Now, in the compressed 
condition in which the Quebec sponges occur, we can, as a 
rule, only perceive those rays of the spicules which lie in 
the exposed plane of the rock, these are generally the four 
transverse rays of the normal spicule, but the two rays 
forming the axis at right angles to the treynsverse rays, are 
not likely to be distinguished, for one would be concealed 
in the matrix immediately beneath the transverse rays, 
whilst the other, projecting above the exposed surface, 
would inevitably be broken away. Consequently it is very 
difficult to determine positively whether the forms with 
four transverse rays exposed on the plane of the.sponge- 
wall, represent the entire spicule,—in which case it would 
be termed cruciform,—or whether one or both of the other 
rays of the normal spicules were originally present. Judg- 
ing by the analogy of allied recent forms, it is probable 
that in most cases these spicules were furnished with a 
fifth ray at right angles to the other four. In the examples 
of Cyathophycus from the Utica shale, are distinct traces of 
a fifth ray in some of the larger spicules, and it can also be 
seen in a detached spicule on a slab from the Quebec group. 
In both recent and fossil hexactinellids, many of the 
elongated filiform anchoring spicules terminate distinctly in 
four short recurved rays, and are thus five-rayed spicules in 
which one ray is greatly developed; but in other instances 
they have simple blunt or pointed ends, and may thus 
represent only one ray or one axis of the normal spicule. 
With one doubtful exception, all the anchoring spicules 
present in the Quebec sponges are merely pointed at their 
distal ends. 
In recent hexactinellid sponges, in addition to the spic- 
ules forming the regular framework of the skeleton, there 
are much smaller spicules of varied forms, imbedded in the 
soft tissues. These, generally known as flesh-spicules, are 
