PORIFERA. I. 



79 



1869. Oceaiiapia Jcffi'cysii Norman, Report Brit. Assoc, for 1868, 334. 



1874. Desmacidon Jcffrcysii Bowerbank, Mon. Brit. Spong. Ill, 157, PI. LXII. 



1882. — — Carter, Ann. Mag. Nat Hist. Ser. 5, X, 121. 



1885. Reiiiera tubulosa Armauer Hansen (non Fristedt), The Norwegian North-Atlantic Exp. XHI, 



Spongiadae, 4. 

 1887. ? Oceaiiapia yobnsta Ridley and Dendy, Challeng. Report, IMonaxonida, XX, 36, PI. IX, fig. 3. 

 1887. Desmacidon Jeffyeysii Fristedt, Vega Exp. vetensk. lakttag. I\', 442. 



1892. Gelliodes cavicornis Topsent, Resultats des Campagn. scient. du Prince de Monaco, Ease. II, 78, 

 PI. Ill, figs. 4 et 9, PI. IX, fig. 12. 



The sponge consisting of a round body zuit/i more or feiver digitate^ branched or unbranched 

 Jistiihv^ ivhich are closed at the ends. The surface slightly shaggy from projecting spicules. Outermost a 

 hard., rindlike layer. The skeleton of the external layer an irregular netivork, chiefly of t/iick polyspi- 

 citlar fibres. In the interior the skeleton consists of scattered needles. Spongin is found to a small degree 

 in the fibres of the rind-layer. Spiciila : Megasclera o.vea o-20 — 0-268""" ; microsclera sigmata 0-014'"'". 



This species which, as is well known, is formed as a globular body from the surface of which 

 branched or unbranched fistula arise, is in the collection only found in fragments, partly pieces of the 

 external hard rind of the globular body, partly broken off fistulte. The largest piece which quite 

 appears to be part of a globular surface, has a greatest extent of ca. 20™ ; it is only convex to a slight 

 degree, and must accordingly be a jiiece of a very large specimen. It has had several fistulse, but 

 they are broken off; at their base they have had a diameter of 40—50™". The thickness of the rind- 

 layer is somewhat varying, about 10 — 15™™. In fragments of smaller specimens the rind is considerably 

 thinner, about 2—3'"'". Of the torn off fistulae (belonging to the large specimen), some are unbranched, 

 while others are divided into at most 4 or 5 digitate branches. The long fistulae have a length of ca. 

 13'^"'; towards the ends they are generally somewhat compressed. The diameters of the unbranched 

 fistulse are at most ca. 20"""; but the branched ones are considerably thicker at the base. All the 

 imdamaged fistuke are closed as the ends, so that it seems that the fistulse are always closed. Th^ 

 colour of the sponge (in spirit) is light yellow. In the earlier descriptions the sicrface is stated to be 

 smooth; this, however, is incorrect; it is even, but slightly shaggy from projecting spicules. As the 

 specimens in hand chiefl\' consist of pieces of the rind-layer, we have only comparatively little of the 

 interior body. This interior consists of a peculiar, loose and pappy substance of a yellowish white 

 colour; when this substance is dried it contracts to a very high degree, becomes dark yellow and semi- 

 transparent, reminding, as stated by Norman 1. c, of wax, although not in consistency, as it is very hard. 



The pores are found copiously as well on the body as on the fistulse in the intervals between 

 the spicules; they are measured to a size of about 0014— 0-057""". ^o oscula are found, and it is 

 doubtful how the facts are with regard to the excurrent canals. As mentioned the fistulse are closed 

 at the ends, but here and in their whole outer part they show a peculiar structure, the dermal mem- 

 brane wanting or being reduced, so that holes appear of the same size as the meshes in the skeleton 

 below; I am, however, inclined to think that this fact is due only to damaging, and if so, the pores 

 of the skin must act both as incurrent and as excurrent openings. On account of the arrangement of 

 the canal system, I suppose, that it is the pores of the fistulse that act as excurrent openings. 



