“Hymerphia vermiculata, Bowerbank.
Sponge. Coating; surface uneven and cavernous; strongly hispid. Oscula simple, dispersed. Pores inconspicuous. Dermal membrane spiculous; specula acuate, long, and exceedingly slender, variable in size, fasciculated? Skeleton and external defensive spicula acuate, large and long. Spicula of the basal membrane inequiacerate, vermiculoid, rather large and stout, exceedingly variable in tortuosity.
Colour. – Dried, light buff yellow.
Habitat. – Shetland, in deep water, Mr. Barlee, Mr. C.W. Peach, and Rev. W. Gregor.
Examined. – In dried state.
I am indebted to my friend Mr. Barlee for this interesting species. I received four specimens, three of which were coating small pebbles. None of them exceeded four lines in diameter and the thickness not more than that of a sheet of paper. The colour is a light buff yellow, and with a lens of two inches focus the long spicula may be seen projecting from the surface of the sponge, like minute bristles. By the aid of a Lieberkuhn and a power of 100 linear, the surface appears very uneven, full of abrupt depressions and elevations, and a few minute simple oscula were apparent.
When a portion of the sponge was removed and mounted in Canada balsam, the dermal membrane appeared to be very delicate, and to be lined with a thin coat of sarcode, but I could not either by this mode of mounting, or by any other means, detect the spicula of that membrane in situ. On treating a piece of the sponge with boiling nitric acid, in a small dished cell, I obtained them in considerable numbers, and the greater portion of them were collected in regular fasciculi; and from this mode of arrangement, and the peculiarities of their structure, there is no doubt in my own mind that they were liberated by the action of the acid from the dermal membrane. They are so slender that they require a linear power of 500 or 600 to define their structure and proportions accurately. The skeleton and external defensive spicula appear enormously large in proportion to the thickness of the sponge and its remaining tissues. The whole of them have the base firmly cemented to the basal membrane, and far beyond its surface, and at right angles to it.
The basal membrane of this sponge presents a novel and very singular appearance. It is abundantly furnished with inequi-acerate vermiculoid spicula lying on the surface of the membrane, and presenting an appearance very like a congregation of the vibriones of sour paste. No two of them are alike in their contortions, length, or thickness, and in their disposition they pass under and over each other in every possible manner, so as completely to form a loose felting of siliceous spicula. The basal ends of the large skeleton ones pass through this stratum of spicula, and in several instances I observed that the points of the vermiculoid ones coiled closely round their bases so as materially to assist them in maintaining their positions on the basal membrane.
The vermiculoid spicula do not appear to be equally abundant in every specimen of the species, as in sponges subsequently examined they were comparatively few in number, and in one case they were dispersed and unconnected with each other, and this did not appear to arise from an immature condition of the sponge, as in other respects it appeared to be fully developed.
I have subsequently received specimens on old shells and pebbles, from the Rev. Walter Gregor, dredged in the Moray Frith, and others from Mr. Peach. None of these specimens exceeded three fourths of an inch in diameter.”
(Bowerbank, 1866)
