130 Rev. T. Hincks’s Contributions towards 
ing the junction of the ribs) passing from the top of the 
ovicell to the opening. 
Loc. Australia, creeping over an alga (Miss Jelly). 
This species is allied to M. pilosa, but differs from it in 
many points. Its most marked characteristic is the very 
curious ribbed ovicell, which occupies a fixed place in the 
colony and is borne on a cell embraced by the branches which 
are given off at intervals from the extremity of the single 
lines. The ocecium is formed by an extension of the aper- 
ture upwards, giving rise to an elongate-oval area bounded 
by a slightly raised margin. On the latter are developed 
seriatim the rib-like processes, which ultimately unite along 
a central line, and constitute the marsupial chamber. These 
must be regarded as a modification of the spines of the zocecial 
aperture. When closely examined the wall of the ocecium is 
seen to be composed of spine-like ribs, united laterally by a 
calcareous expansion, but often slightly disjunct at the base. 
In this species, therefore, the marsupium is formed of the upper 
portion of the zocecial aperture (which is much extended in the 
ovicelligerous cell), roofed in by a number of marginal spines, 
which meet and are soldered together at the extremities, and 
are united along the sides by a calcareous lamina. It is a 
very simple modification of certain elements of the zocecium, 
by which the latter is divided into two chambers—one for the 
polypide, the other for the embryo. 
Membranipora velata, n. sp. 
(EIR Ne ties3 9) 
Zoecia ovate, pyriform, or hexagonal (somewhat irreeular 
in shape), distinctly quincuncial, placed close together; aper- 
ture occupying the whole front (except in the pyriform 
cells), ovate, the cell-wall around it slightly roughened or 
crenate, with a membranous roofing stretching across it on 
a level with the margin, which it overspreads. Avicularia 
sessile, on a distinct area, scattered amongst the zocecia, 
always wedged in between two cells at their upper extre- 
mity; beak not prominent; mandible pointed, flattened, 
directed obliquely upwards. Owciwm very shallow and in- 
conspicuous, just covering the extremity of thecell. Zoariwm 
presenting a flat uniform surface of a dark brownish colour, 
caused by the overlying membrane. 
Loc. Santa Cruz, California, on shell (Miss Jelly), 
The brownish appearance of the zoarium, which is due to 
the extension of the membranous front wall over the margin 
of the cells, is a distinguishing character. There is much 
irregularity in the shape of the cells; in many cases they are 
