20 POR1FERA. II. 



and as foreipes also occur outside of the genus Forcepia, and the occurrence of these bodies therefore 

 scarcely alone is sufficient for the establishing of a genus, I think it most natural to refer the present 

 species to the genus Esperiopsis. Topsent (Resultats des Campagn. scient du Prince de Monaco, 

 Fasc. II, 1892, 100, PI. VI, fig- 5, PI. X, fig. 9) has established a species Forcepia versatilis wanting 

 dermal spicules; but in embryos found in the sponge small diactinal spicules were found which 

 Topsent takes to represent the dermal spicules, but they are not further developed, so that the 

 species later on has none of them. This species, however, is no Foreefia, but an Asbestopluma, as will 

 be more particularly mentioned under this genus. 



6. E. flagellum n. sp. 

 PI. IX, Fig. 1 a— h. 



Jncrusting; the surface slightly uneven from projecting bundles of spicules ; the dermal mem- 

 brane thin without spicules. The skeleton irregular consisting of polyspicular fibres and bundles of spicules. 

 No spongin. Spic?ila: Megasclera styli o-jp — 0-44"""; microsclera of four forms, isochelce pa Una to 1 of 

 two forms, large ones 0-04 j — o-o8j""". small ones 0-018 — 0-021""": common sigmata o-oq$— 0-2 $"""; flagel- 

 late sigmata o~oj — owj. 



This species grows as a quite thin incrustation on a dead branch of Ampheiia oculata otherwise 

 very much overgrown by Bryozoa. On the branch are further found an fophon, a Mycale placoides, 

 and a Hamacantha Bowerbankii. With regard to the outer form of the species can only be said that 

 it is a quite thin crust; its contour is irregular, following the form of the substratum, and the limits 

 are otherwise most frequently only seen with much difficulty. Its greatest extent may be given to 

 about 40""", the thickness is only one or two millimetres. The colour (in spirit) is yellowish or slightly 

 reddish yellow. The consistency is loose. The surface has small and scattered projections owing to 

 projecting bundles of spicules, but by examination with a magnifying-glass they are only very little 

 conspicuous. The dermal membrane is thin, without any particidar skeleton only provided with micro- 

 sclera. Oscula and pores have not been found. 



The skeleton consists chiefly of short fibres or bundles of spicules rising from the base up 

 through the sponge. Sometimes they meet upwards pyramidally^ and give rise to the unevennesses 

 of the skin. They may also be longer and run almost parallel to the surface finally bending into it; 

 these longer fibres may also be branching. Here and there scattered bundles of spicules and a few- 

 scattered spicules are seen. The fibres are polyspicular, and the average thickness may be given to 

 o - 05 mm . Spongin has not been observed and seems not to be found. 



Spicula: a. Megasclera are slender, straight styli, generally with a very slightly swollen head 

 end, and thus approaching subtylostyli; they are of about equal thickness in their whole length, and 

 the point is short and bounded by rather straight lines. The length is rather constant, varying from 

 0-39 — o-44 mm , the thickness is o - oo6 — o-oc>7 mm . Developmental forms of the styli occur singly, down to 

 quite fine ones that are long tapering, b. Microsclera; of these four forms are found, two forms of 

 isochelse palmatse, larger and smaller ones, common sigmata, and flagellate sigmata. 1. The large iso- 

 chelse are straight, the alas stretch so far down the shaft, that the free middle part is less than one third 



