large, 0·36 mm. × 0·01 mm. They enter sparingly into the wall of the radial tubes. They often reach from the gastral wall, and they project from the outer surface of the sponge, entering, in their distal portion, into the composition of the dermal cones. They taper evenly to a sharp point at either end. (c.) Oxea of the dermal cones: These are slender spicules, twisted after the fashion of many “mortar spicules.” Size, 0·12 mm. × 0·003 mm. (d.) Oxea of stolon: These are straight or slightly curved, and sharp-pointed. They echinate the surface freely.

Triradiate spicules: These are all sagittal. They may or may not be slightly irregular. (a.) Subgastral: Paired rays short and slightly curved towards the basal ray, 0·03 mm.; basal ray, 0·17 mm. × 0·008 mm. The paired rays are almost at right angles to the basal ray. (b.) Parenchymal: Paired rays sometimes nearly as long as basal ray, making an angle of about 120° with it. These spicules also enter into the composition of the distal cones. (c.) Triradiates of stolon, like the gastral triradiates, but often having the tips of the paired rays strongly recurved.

Quadriradiates: These occur in the gastral cortex and in the stolon. They are all sagittal. The angle made by the paired rays with the basal ray may be from 90° to about 145°. Basal ray, 0·14 mm.; oral ray, 0·13 mm.; apical ray, 0·1 mm. Greatest breadth, 0·005 mm.

All the spicules of this sponge are very graceful and slender. The flagellated chambers are hexagonal in section, and the intercanals triangular.

In spiculation this sponge resembles Sycon carteri, Dendy, from which, however, it differs in the more slender character of all its spicules, in the shape and size of the oxea of the distal cones, and in the presence of the parenchymal oxea. To a less extent it resembles Haeckel's Sycandra ampulla, from which, however, it is quite distinct. Colour, brownish-white.

Locality: Whangaruru and adjacent coast of North Auckland, between the tide-marks.

Note.—Since this description was in type I have found the sponge in a much finer form at Plimmerton, in Cook Strait.

Sycon ornatum, n. sp. Plate XXXI., figs. IIa., IIb., and Plate XXXII., fig. II.

Sponge solitary, tubular, generally broader near the base than above; about 15 cm. in height, from a quarter to half of the height being made by a narrow spicular funnel, provided at its mouth with a delicate peristome and, occasionally, with a thin spicular veil. To the naked eye the body of the sponge is hispid in appearance, from the oxea of the distal cones. This appearance is not noticeable in the funnel, although the funnel