Dr. G. J. Hinde on Fossil Calcispongic. 201 
species, Lelapia australis (Proc. Zool. Soc. 1867, p. 557). It 
is interesting to note that the two species with this spicule 
described by Hackel are also found on the south coast of 
Australia and in the Indian Ocean. If we turn to Hiickel’s 
figures of the different forms of spicules of Leucetta pandora, 
on Taf. xxili., which are magnified to the same scale of 200 
diameters as those on my Plate XII. we find that the forms 
which he terms “ anchor-shaped triradiates,”’ with recurved 
sagittate rays (¢), correspond with the pickaxe spicule of my 
fig. 8; the fork-shaped spicules with open prongs (fig. 6) re- 
semble those which Hickel terms completely irregular trira- 
diates (py); whilst the small fork-shaped fossil spicules 
(figs. 13-15) may be compared with those of Hickel’s fig. h ; 
the fossil spicules, however, are much smaller and slenderer 
forms than the recent, and the basal ray gradually tapers 
instead of being swollen at its extremity. The variability of 
the spicules in this fossil seems to be almost as great as in 
the recent sponge, of which Hiackel states that its skeleton 
may be considered a complete armoury for all possible forms 
of triradiate spicules. 
Judging from the form and canal-system this fossil species 
appears to belong to Zittel’s genus Sestrostomella. Up to 
the present, however, the spicular characters of the type 
species of this genus have not been ascertained; and until 
these are known the generic position of this species rust be 
regarded as merely provisional. 
Horizon and Locality. Cretaceous, Vaches Noires, near 
Havre. 
Collection. British Natural-History Museum. 
Sestrostomella clavata, n. sp. 
(Pl. X. fie. 5; Pl. XII. figs. 16-25.) 
Sponge compound, depressed, spherical in outline, consisting 
of numerous cylindrical individuals, mostly free at their sum- 
mits, but partially united laterally, which grow from a central 
mass. There are no signs of any stem or expanded surface 
of attachment; but on the underside there are two smooth 
small patches on which the sponge seems to have rested 
during its growth. The individuals are from 8 to 10 millim. in 
diameter, with rounded summits. The cloacal aperture is about 
2°5 millim. in width ; in some examples it appears to be re- 
placed by a few oscules or canal-openings. Straight open 
canals extend from the summit down the sides of some indi- 
viduals. ‘The outer surface exhibits only the irregular inter- 
spaces between the fibres. 
Ann. & Mag. N. Hist. Ser. 5. Vol. x. 14 
