15. Pectispongilla aurea*, Annandale.
Pectispongilla aurea, Annandale, op. cit., p. 103, pl. xii, fig. 2.
Sponge forming minute, soft, cushion-like masses of a deep golden colour (dull yellow in spirit); the surface smooth, minutely hispid. One relatively large depressed osculum usually present in each sponge; pores inconspicuous; dermal membrane in close contact with the parenchyma.
Skeleton consisting of slender and feebly coherent radiating fibres as a rule two or three spicules thick, with single spicules or ill-defined transverse fibres running horizontally. Towards the external surface transverse spicules are numerous, but they do not form any very regular structure.
Spicules. Skeleton-spicules smooth, sharply pointed, straight or nearly so. Gemmule-spicules minute, with the stem smooth and cylindrical, relatively stout and much longer than the comb at either end; the two combs equal, with a number of minute, irregularly scattered spines between the two outer rows of stouter ones. No free microscleres.
Gemmules minute, spherical, with a single aperture, which is provided with a very short foraminal tubule; the granular coat well developed; the spicules arranged in a slanting position, but more nearly vertically than horizontally, with the combs pointing in all directions; no external chitinous membrane.
| Length of skeleton-spicule | 0.2859 mm. |
| Greatest diameter of skeleton-spicule | 0.014 mm. |
| Length of gemmule-spicule | 0.032-0.036 mm. |
| Length of comb of gemmule-spicule | 0.008 mm. |
| Greatest diameter of shaft of gemmule-spicule | 0.004 mm. |
| Diameter of gemmule | 0.204-0.221 mm. |
The gemmule-spicules first appear as minute, smooth, needle-like bodies, which later become roughened on one side at either end and so finally assume the mature form. There are no bubble-cells in the parenchyma.
15a. Var. subspinosa*, nov.
This variety differs from the typical form in having its skeleton spicules covered with minute irregular spines or conical projections.