66 THE VOYAGE OF H.M.S. CHALLENGER. 



forei"ii bodies — all precisely as in the original specimen of the form from Lesina ; and 

 as its internal oro-anisation also does not deviate from that of Cacospongia collectrix as 

 described by F. E. Schulze, there is no room to doubt the specific identity of both these 

 specimens. But the matter is quite different with regard to the Challenger specimen 

 from Japan. Its internal structure also does not differ from that of a typical Eusjwngia 

 or Cacospongia, but — and this is the salient point — 1 was unable to make out whether 

 this specimen really does possess any differentiated horny skeleton. This was owing 

 to its minuteness, its dimensions being on an average as follows : — length 22 mm., 

 height 7 mm., breadth 10 mm. The half of the specimen has been sacrificed to the 

 decision of the above question ; the result of a lasting treatment with hot water 

 and ammonia was a heap of sand-grains and a single 2 mm. high horny tree also very 

 rich in foreign enclosures. Is it to be regarded as produced by the sponge itself 1 Is it 

 also nothing but a foreign enclosure, like what Marshall states ^ of the specimens of 

 Psammopemma densum he had for examination ? All this remains an open question. 

 That our specimen is a horny sponge is quite plain, the foreign bodies enclosed in 

 its parenchyma being undoubtedly surrounded with obvious horny substance ; that, 

 being a Keratose sponge, it is also a Spongid is demonstrated by its internal struc- 

 ture, but whether it is to be classed in the species Cacospongia collectrix, and not 

 to be regarded as an analogue of Psammopemma in the family of Spongidte, will be 

 decided but by later investigations. Of course under such circumstances I prefer to 

 abstain from the creation of a new name. 



Both the specimens proved to contain filaments, but while the specimen from Japan 

 is strikingly poor in them, the specimen from the Philippine Islands on the contrary 

 is overloaded with them in not a less degree than the Challenger sj)ecimens of Stelospongos 

 longispinus or Cacospongia irregularis. 



Colour. — Specimen from PhUippiue Islands, pale greyish-yellow. Specimen from 

 Japan, outer surface grey, parenchyma dirty yellowish. 



Habitat.— ^ta-tion 203, October 31, 1874, lat. iT 6' N., long. 123° 9' E.; depth, 

 12 to 20 fathoms; mud. Station 233a, May 19, 1875, lat. 34° 38' N., long. 135° I'E.; 

 depth, 8 to 50 fathoms ; sand. 



Stelospongos, 0. Schmidt. 



Spongida3 with comparatively thick skeletal fibres united in separated columns 

 directed more or less regularly radially from the basis of the sponge towards the outer 

 surface, and consisting each of a compact network of vertical, primary, and horizontal 

 secondary fibres. 



1 Zeitschr.f. wiss. Zool., Bd. x.\xv. p. 114. 



