— 36 — 
unequal in length und occasionally one is aborted and the spi- 
cule is bifid. I have not noticed any specimens of this form 
with compound or bifurcate rays. There is considerable va- 
riation in the size of these spicules; a large specimen (fig. 17) 
measured 3,15 mm. long by 0,09 mm. wide. A smaller form 
(fig. 19) is 1,01 mm. long and the thickness of the shaft is 
0,045 mm. 
A spicule closely resembling fig. 17 is figured by Dr. Bow- 
erbank from Geodia Zetlandica (Mon, Brit. spong. Vol. III, 
pers; 21. Vo fe38), 
Geodia? sp. 
(Plate II, fig. 16). 
Spicule with a delicate, straight, gradually tapering shaft 
and three slender simple rays, unequal in length and recurved, 
each of the rays being of nearly the same thickness as the 
shaft, Length (incomplete) 1,05 mm.; width 0,067 mm. Very 
rare. This spicule is of the same character as the preceding, 
but the arms are recurved, anchor-like. 
é 
Tethya? sp. 
(Plate TH, figs. %,,2: 13, 14). 
Simple trifid spicules with a relatively very variable length 
of shaft, which is straight or curved, gradually tapering and 
in most instances obtusely pointed; the arms of the head 
rays are very long, frequently of unequal length in the same 
spicule; stout, conical, curved, pointed and directed forwards 
at a very open angle with the shaft. There is a very great 
amount of variation in the length and in the relative propor- 
tion of the arms of these spicules; in some examples, one of 
the rays becomes nearly as long as the shaft. In no instance 
do the arms bifurcate. The length of one of the largest 
specimens (fig. 2) is 4,025 mm.; width of shaft 0,247 mm,; 
width of head rays 1,35 mm. In another form (fig. 13), in 
which the shaft is constantly straight and but little stouter 
than the arms, the total length of the spicule is 1,8 mm. dia- 
