var. spinispiculum, Crér. 157 
short straight acerates, minutely spined or serrated also over 
their distal portion, sharp-pointed, or terminated by a pin-like 
inflation at. the distal end; shortest form seen about 1-300th 
of an inch (fig. 4, ¢ and d). 4, long, straight, smooth, 
slightly tapering from a more or less slightly enlarged lanceo- 
late or simply pointed proximal end to a curved free extre- 
mity, about 1-300th inch in length, serrated over the convexity 
and ending in a sharp smooth spineless point, which is turned 
in the opposite direction ; serratures more or less distinct and in 
many instances evidently directed outwards, diminishing in 
size towards either extremity, the whole spicule varying 
in length from 1-461st of an inch, which is that of the 
smallest above mentioned, to 1-6th inch, which may be the 
maximum length of the longest (fig. 3). 5, like the last 
in form, but straight throughout, terminating in a very fine 
point, serrated on one side only, in two approximated broken 
lines, for about the same length as the foregoing, but with the 
teeth much larger and directed ¢nwards, diminishing in size to 
the distal extremity as they increase in size in the opposite 
direction; length variable, viz. from about 1-300th of an inch, 
which is that of no. 3 above mentioned, to 1-25rd inch, which 
is the maximum of that observed (fig. 4). 6, gently curved 
once or twice, variable in length, but much shorter than the 
foregoing ; smooth and pointed in the imner or proximal por- 
tion, serrated and abruptly or capitately terminated at the 
other; teeth as in the foregoing, on one side only, recurved 
and arranged in two approximated broken lines extending 
backwards for about 1-3338rd inch from a slightly inflated head 
with 0-3 spines, directed backwards like the anchoring-spicule 
of Euplectella ; length of longest observed about 1-36th inch 
(fig. 5). All these forms in jront of the stem are directed 
forwards, and in all not only is the length very variable, as 
may be seen from the measurements above given, but the ser- 
ration or spination and general form also are much modified, 
especially in the smaller kinds (nos, 2 and 3), while in the 
larger and longer (nos. 4 and 5) they are more persistent ; and 
while no. 4 prevails towards the larger end of the body, the 
more distinctly spined or toothed spicules, nos. 5 and 6, to- 
gether with 2 and 3, prevail towards the root. Peristome, 
vent, or mouth, as it has unfortunately been termed, composed 
of two portions, viz. a “neck ” or “ collar” (fig. 2, 2) and a 
“crown” (fig. 2, g), the “collar” consisting of a contracted 
portion of the body about 1-G60th inch in longitudinal dia- 
meter, naked or uncovered by the conuli, which do not extend 
further forward than this point, and thus the distinction is 
clearly defined ; composed outside of a layer of stout, smooth, 
