REPORT ON THE KERATOSA. 45 



Colour. — Pale greyish-yellow ; skeletal fibres dirty greyish. 



i/'a^^to^.— Station 18G, September 8, 1874, lat. 10° 30' S., long. 142° 18' E. ; depth 

 8 fathoms ; coral mud. 



Psammoclema foliaceum, n. sp. (PL III. fig. 7). 



Like Psammoclema ramosum, the species in question was brought home in fragments, 

 all, however, in both cases belonging to one specimen. When put together, the fragments 

 of the Challenger Psammoclema foliaceum form a whole which may be compared with my 

 drawing of Carteriospongia radiata, but which is approximately four times as large, with 

 walls from two to four times as thick in different parts of the body, and with surfaces 

 of a rather shagreen-like appearance and not distinguished by the system of longitudinal 

 ribs. The resemblance in the form ; the fact that, as regards the anatomical structure of 

 the canal system, Psammoclema is closely allied to Carteriosjjongia ; and again, that most 

 of the representatives of this latter genus also possess fibres full of foreign enclosures ; all 

 render the form I am now describing extremely interesting from a phylogenetic point of 

 view. This has led me to make greater endeavours to find out its histological structure 

 in the hope of discovering in it the anastomosing "Strange" of F. E. Schulze, the function 

 of which is of course doubtful, but which a.re so very characteristic of Carteriospongia 

 and of all the Spongidre generally. The specimen proved, however, to be so very badly 

 preserved that I had to be content with making out its anatomical organisation, and thus 

 assigning to it a definite systematic position. 



A portion of its skeleton is represented on PL III. fig. 7 ; like that of Psammoclema 

 vosmaeri, it is of a dirty-greyish colour, due to the abundance of foreign enclosures in its 

 fibres, but the meshes are larger, and when seen against the light the primary fibres 

 become very clearly visible. I characterise the species exceptionally by its external 

 shape, but of course I am uncertain whether I am right in this proceeding. Later 

 investigations wiU decide the question. 



Colour. — Black ; skeleton grey. 



Habitat. — Station 162, April 2, 1874, ofi" East Moncceur Island, Bass Strait; depth 

 38 fathoms ; sand and shells. 



Psammopemma, Marshall. 



Spongelidse without any differentiated skeletal fibres, the supporting skeleton being 

 represented by foreign enclosures lying separately in the parenchyma, and the secretion 

 of the horny substance having been reduced to the formation of only a thin envelope 

 around the enclosed foreign bodies. 



