gg PORIFERA. I. 



Desmacella O. Schmidt. 



The form varying, massive and irregular, or erect and of a more definite for tu. leaf-shaped or 

 more or less calicular. The skeleton consists of long, zuell developed branched fibres, the spicules of which 

 are united by a most frcquoitly slight mass of spongin. Spiciila: Alcgasclera monactiiial. styli (some- 

 times tylostyli) ; microsclera may be combined in various 7miys, sigmata alone, or sigmata of tzvo to three 

 sizes, and rhaphides of one to three sizes, and most frequently small coini/m-shaped styli (cominata) (per- 

 haps always found at this combination of spic2iles) or finally rhaphides alone. 



Of this genus we have several species, all, however, nearly related to each other; these species 

 are grouped round Desmacella Peachii'&OMd.y and agree in the fact that with regard to microsclera they 

 have sigmata at least of two sizes, rhaphides of one or more sizes, and all, I suppose, small comma- 

 shaped styli. The question whether we have here one varying species or several species, may be 

 rather difficult to decide; the spicules, however, seem here, as in other places, to give rather sure 

 and constant species-characters, even if the differences are small. It may also give rise to some diffi- 

 culty to decide whether any of the species in hand — and if this is the case, then which of these 

 species — are identical with earlier described species, as the difference of the spiculation and the forms 

 of the spicules are not given with sufficient distinctness in the earlier descriptions. When in the 

 following I have determined one of the species before me as Bowerbank's D. Peachii, I have there- 

 fore made this determinatiou with some reservation. 



I. D. capillifera Levinsen. 

 PI. XVI, Fig. I a-g. 

 1886. Gellius capilliferus Levinsen, Dijmphna Togtets zool.-bot. Udbyttet, 357, Tab. XXX, figs. 7 — 10. 

 1896. Desmacella Pcacliii var. groenlandica Lambe, Sponges from the Atlant. Coast of Canada, Trans- 

 act, of the Ro}'. Soc. of Canada, Ser. 2, II, Sect. IV, 186, PI. I, figs. 5, 5 a — e. 



Form? The dermal mei/ibrane thin, only provided with microsclera. The skeleton consists of 

 powerful fibres with little spongin, Spictcla: Megasclera styli o'j — rS'""" ; microsclera sigmata of two 

 sizes, the larger o-o.^ — o-i""", most frequently in bundles, the smaller o-oig — o-oji"""; rhaphides o-ij^ 

 — o-ig""", most frequently in bundles; commata 0-02'"'". 



Of this species we have only a little piece attached to a Bryozoa, and presumably this piece is 

 only the nethermost part of a sponge that has been broken off. Thus with regard to outer charac- 

 teristics I cannot add much to the descrif)tion given by Le\-iusen I.e., which is also based on frag- 

 ments. The dermal membrane is thin, and of spicules it has only sigmata and rhaphides; sigmata are 

 very abundant, especially the smaller form, and the rhaphides occur partly scattered, but most fre- 

 quently in bundles. These bundles seem to form a kind of reticulation. The colour (in spirit) is 

 yellowish gray. Lambe 1. c. describes the dermal membrane in the same way, but has also found 

 circular openings in it of an average size of 075""", which he regards as oscula. The skeleton has 

 the structure characteristic of the genus consisting of fibres the spicules of which are united by 

 spongin. 



