4 R. KIRKPATRICK. 
and possibly also of a root-tuft. A few external (? velar) hypodermal oxypentactins are 
present on the surface, and little tufts of broken-off basalia project from the rounded 
base of the specimen. There may be a well developed root-tuft in complete specimens ; 
further doubts on this point were suggested by the condition of four specimens of a 
species of Craniella from the Antarctic, three being almost smooth at the lower end, owing 
to the root-tuft having been detached in dredging, whereas the fourth has a large root-tuft. 
The dimensions of the specimen are as follows :—Height, 14cm. ; greatest breadth, 
Gem. ; diameter of orifice, which is slightly torn, about 4em.; greatest thickness of 
wall, 1°1cem. 
The lumen of the deep gastral cavity is occupied by numerous scattered internally 
projecting pleuralia, which have been driven in from the outside. The circular 
openings of the ostia, about 1*5mm. in diameter, are clearly visible beneath the dermal 
layer ; also the slightly larger postica are perceptible beneath the gastral layer, which 
roofs them over with a fine lace-like reticulum. 
Skeleton. The skeletal framework is formed of bundles of diactins ; there are 
no large hexactins. 
Spicules. ‘The principalia are oxydiactins, about 7000 x 80p in size, with fine 
tapering ends smooth or only very slightly spimed. A much smaller kind, 1400 x 18p, 
separate, and not in bundles, with roughened ends and four central knobs, is common 
beneath the dermal and gastral membranes. 
The autodermalia (IV. 1a) are spined hexactins, each ray being 131 in length 
and 15°54 broad at the base, slightly tapering to a blunt extremity; pentactins 
(LY. 1b), with the odd ray proximal, occur, but very rarely. 
The hypodermalia (IV. 1d, d’) are oxypentactins with slender ameoth tapering 
paratangentials, each about 2700 x 40m, the rays being either orthotropal or 
anorthotropal. 
The autogastralia (IV.1d°) are spined hexactins with slightly longer and more 
slender and sharply pointed rays than the autodermalia, each ray being 1836 x 7° 5p. 
The intermedia, Holoxyhexasters* (IV. le) and hemioxyhexasters (IV. le’), 
varying in diameter from 100 to 120m, are common. Monoxyhexasters* (IV. le’), 108u 
in diameter, occur only rarely. Medium-sized holodiscohexasters (IV. 1f, f*), from 
80-100 in diameter, are also rare ; the short slender primary rays, about 7p in length, 
base of the ray, and that the remaining portion of the ray is devoid of any trace of an axial canal, that it is, 
in fact, more of the nature of a spine. Secondly, in many instances, all the transitions can be traced from 
holohexasters, through several grades of hemihexasters to monohexasters. In a preparation of Rossella racovitze 
Topsent, for example, these transitions can be traced in a crowd of discohexasters, the monodiscohexasters having 
short thick primary rays with the axial canal extending only to the point where the thick portion (primary ray) 
joins the more slender solid terminal portion. To call such spicules as these last disecohexactins would be to 
lose sight of the fact that they clearly have six primary and six single secondary rays, for the latter do not lose 
the character of being secondary simply because they are single. A genuine hexactin would, by its definition, 
have no secondary rays. The designation ‘ hexactinose,’ used by Ijima, would, perhaps, be better written 
‘“‘hexactinoid,” or hexactin-like, but even this term is not without objection, since such a spicule with its primary 
and secondary rays is seen, under a high power, not to resemble a true hexactin. Accordingly the prefixes 
“holo-,”’ “ hemi-,” and “mono-,” added to ‘“oxy-” or ‘“disco-’’ hexaster, are suggested as indicating and 
defining the form and relationship of these spicules. The following figures show the limitation of the axial 
