CALCAREOUS SPONGES—BENDY. 
9 
shrinkage, but they are evidently oval or subspherical in form and about 0-14 mm. in 
diameter. They have numerous prosopyles as usual. The exhalant lacunae lead into 
wide, exhalant canals which converge to open side by side in the floor of the vents. 
Histologically the specimen is so badly preserved that it is impossible to say 
anything definite about the position of the nuclei of the collared cells, but it seems safe 
to assume that it is basal. 
The skeleton consists of regular or subregular triradiates, lying tangentially in 
the dermal and gastral membranes and irregularly scattered in the choanosome, but, 
in the latter case, in such a way that, as seen in sections, they tend to enclose hexagonal 
areas more or less free from spicules. The choansomal skeleton is not very dense. 
There appear to be no sagittal spicules round the margins of the vents. 
Spicules : — 
Regular or subregular triradiates (fig. 7), with approximately equal rays and 
angles. Rays straight, conical, rather long and slender, fairly sharply pointed, varying 
greatly in size up to about 0-36 by 0 035 mm., but such large ones are extremely rare. 
This species might very well fall within the wide circle of forms embraced by 
Haeckel’s Leucetta primigenia, but, as I have already pointed out [1913] in describing 
my Leucetta pryiformis, it is hardly possible to disentangle all these forms from one 
another. Moreover, none of them seemed to resemble Leucetta antarctica at all closely 
as regards external features, which are probably sufficiently characteristic to distinguish 
the species from any previously described. 
Register No., Locality, &c. —VI, Station XII (Lat. S. 64° 32', long. E. 97° 20'), 
110 fathoms, 31st January, 1914. 
Leucetta macquariensis n. sp. 
(Plate I, figs. 3a-3d, 8a-8d). 
There are eleven specimens of this species, all from the beach at Macquarie 
Island. The characteristic external form is massive, cushion-shaped, with convex 
upper surface and flattened base (figs. 3a-3c). Large specimens tend to become cavernous 
by the enclosure of external spaces in the process of growth. The upper surface is 
thrown into a network of irregular ridges and valleys, like a miniature mountain range, 
the summits being represented by small mammiform projections each bearing a small 
vent. Usually these projections are but slightly prominent, but in R.N., V. 2 (fig. 3d), 
which differs considerably in appearance from the other specimens, they may attain 
a height of 8 mm. The vents range up to about 2 mm. in diameter, but are usually 
much smaller, and sometimes they are arranged in more or less definite rows. Their 
margins are usually naked, without conspicuous collar or fringe. When viewed under 
a pocket lens the surface of the sponge has a minutely granular appearance. The 
largest specimen (R.N. I. 1), which may be taken as the type, measures about 40 mm. 
in length by 25 mm. in breadth, and 20 mm. in height. The smallest (R.N. I, 9) measures 
