Dysidea fragilis, Johnston

1. Dysidea fragilis, Johnston View in CoL .

Massive, sessile, simply convex or lobed. Consistence soft and resilient when fresh, firm when dry. Colour, when fresh, faint violet or whitish grey, sponge-yellow when dry. Surface conulated in much relief; conuli held together bya soft reticulated fibrous membrane. Pores in the interstices of the reticulation. Vents here and there, chiefly on the most prominent parts. Structure fibro-reticulated; interstices tympanized by the parenchymatous sarcode traversed by the branches of the excretory canal-systems. Fibre arenaceous throughout. Size variable.

Hab. Marine.

Loc. British coasts generally.

Obs. The above description chiefly applies to the living or fresh state of the sponge, which, after the specimen has been torn off the rocks and the sarcode washed out by the waves, may be found on the beach in the fragile condition, and this probably led Johnston, who might not have seen it under other circumstances, to give it the above designation. When gathered from the rocks and dried directly it presents the conulated state above mentioned, which renders it, as before stated, very much like Spongelia pallescens under similar circumstances. Inserted for comparison.

For a short description of the variety in which the conuli are turned into round arenaceous balls, and for which I have proposed the name of “ Dysidea granulosa, " see ‘ Annals ’ of 1881 (vol. vii. p. 376).