jQQ PORIFERA. I. 



The form irregular, most frequently roundish, fiibcroiis, or lobate. The surface finely shaggy 

 from projecting spicules ; the drruial membrane provided 7vifh a reticulation of spiculo-fibres. Oscula 

 scattered, formed as loia cones. The skeleton an irreg?ilar netzvork of polyspicular fibres, between zvhich 

 irregularly placed spictdes and bundles of spicules are found. Only very little spongin. Spic7ila : 2Jega- 

 sclera styli o-jS — o-^/"""; microselera diancistra of three forms, large ones o-rj/ — o-iy8""", middle ones 

 0-04^ — 0-0J7""", small ones 0-021 — o-028"""; toxa o-op2 — o'/j/""". 



This species is of an irregularly tuberous or round-lobate form; most frequently the specimens 

 are more or less irregularly roundish, they are not rarely somewhat flat, or quite irregularly lobed and 

 folded. They are often with a larger or smaller part of the surface attached to shells of Mollusks, 

 Brachiopods, Bryozoa, etc., but we have also some whole and undamaged specimens that are not seen 

 to have been attached. The largest specimen in hand, which is of a flat form, has a greatest extent 

 of 95'""', and a thickness of ca. 35'""", but the most frequent size of the specimens, measured in the 

 greatest extent, is between 30 and 60™™. The consistency is rather solid. The colour (in spirit) is 

 light yellowish white or yellowish gray, sometimes a little darker passing into brownish. On account 

 of the dermal reticulation the sitrface has a net-shaped sculpture, but is besides finely shaggy from 

 projecting spicules. The dcrinal membrane is provided with a fine reticulation resembling that of 

 Halichondria panicea, and the reticulation may, as in the latter species, sometimes be more coarse and 

 irregular, or the spicules may be closer packed without forming what may properly be called a net- 

 work. Especially in the nodes of the network prominent spicules project through the skin making 

 it shaggy. 



Oscula are found in different numbers scattered on the sponge; 'Caws, specimens may be found 

 with only one osculum, while most have a larger number; the mentioned largest specimen, for instance, 

 has ca. 10 oscula. They are formed by the thin dermal membrane rising into a broader or more 

 pointed, but always rather low cone with a larger or smaller opening. The oscular cones are not 

 more than a few millimetres in height. The net-shaped arrangement of the spicules in the skin passes 

 in the oscular cone to an arrangement where the spicules are situated parallelly to the longitudinal 

 axis of the cone, and they are h'ing rather close to each other; at the edge of the oscula, therefore, 

 they project close to each other, forming a circle. The pores are found in large numbers in the meshes 

 of the dermal reticulation, most frequently only one or a couple of pores in each mesh; they are cir- 

 cular or oval, and have been measured of a size of o'Oj — 0-178™"'. 



Although the form of the species is irregular, its external shape is nevertheless rather charac- 

 teristic and easily recognizable; especially the frequently found, roundish lobes separated by more or 

 less deep folds, together with the net-like scidpture of the surface, and the form of the oscula are 

 characteristic of the species. 



The skeleton consists of polyspicular fibres chiefly running longitudinally, but with a somewhat 

 irregular course on account of the form of the sponge; in some places they are vertical on the surface, 

 and in the projecting lobes they run longitudinally, but upon the whole they run from the base of 

 the sponge towards the surface; on a section of the s^Donge it will therefore generally be possible by 



