358 
Mr. H. J. Carter’s Contributions 
The Sceptrella. 
Sceptrella , meaning a little sceptre, differs from Spinispirula 
in having a cylindrical, straight shaft with its spinal develop¬ 
ments arranged in groups circularly about the ends, and at 
more or less equal distances on the shaft. The spines may 
be smooth and simple, as in Podospongia Loveni 7 Bocage 
(Joum. d. Sci. Math., Pliys. et Naturelles, no. iv. Lisbonne, 
1869, pi. x. fig. 1, &c.), or microspined, as in Sceptrella 
regalis , Sdt. (Spongien d. atlant. Gebietes, p. 58, Taf. v. 
fig. 24, a) ; or the groups on the shaft may be transformed 
into circular plates with serrated margin, as in Latruncula 
cratera 7 Bocage {op. et loc. cit. 7 pi. xi. fig. 2, c, d f e ) ; for 
illustrations of these respectively see PI. XXIX. figs. 13, 14, 
and 15; or the plates round the shaft may be cup-shaped 
(figs. 16, 17, and 18), or the shaft stout with few and large 
spines (fig. 19), or the circular plates inflated on the margin 
and, together with most of the shaft, uniformly covered with 
minute spines (fig. 20); or, finally, the shaft may be almost 
obscured by the groups at the extremities being transformed 
into a single globular inflation, and those on the shaft into 
four or more such globular inflations, all microspined (fig. 21) ; 
the latter is almost a fac-simile of one of the spicules charac¬ 
terizing Hancock’s genus Thoosa among the excavating 
sponges, to which I have already alluded. All the illustra¬ 
tions of the sceptrella are drawn on the same scale for com¬ 
parison ; and figs. 16 to 21 inclusive are present in greater or 
less number among my mounted specimens of the minute 
detritus from the root-bunch of Euplectella cucumer , obtained 
at the Seychelles, in which the number of known and unknown 
forms of spicules of the Spongida is truly wonderful, to say 
nothing of the other siliceous organisms, viz. the Radiolaria 
and Diatomacefe, all of which, having been boiled in nitric 
acid, are preserved (at the expense, of course, of the calca¬ 
reous Foraminifera) , mixed up with gold dust and blue sap¬ 
phire, &c. 
As regards the extent to which the sceptrella under various 
forms occurs in the Spongida, I have never seen it in any 
species but those which I should be inclined to place among 
the Suberitida in the order Holorhaphidota, viz. those above 
mentioned, i. e. Axos spinipoculum , Stellettinopsis simplex , 
and perhaps Corticmm Wallichii , together with the sponges 
from which the sceptrellse in the mounted detritus from the 
root-bunch of Euplectella cucumer came, a few only of the 
forms of which have been briefly described and added to the 
illustrations of this beautiful flesh-spicule. 
