60 THE VOYAGE OF H.M.S. CHALLENGEE. 



apparatus is represented by a large meshed thoroughly irregular basal network of the 

 skeletal fibres, with numerous ascending branches directed towards the outer surface, 

 with a denticulated appearance due to conuli, about 075 mm. high and 3 to 4 mm. 

 distant from one another. All the fibres are approximately of the same thickness 

 (0'18 mm. on an average), and all cored in their central part, very scantily, however, 

 with foreign bodies. As before remarked, the species would be referred by 0. Schmidt 

 to his subgenus Sarcotragus, the filaments filling its parenchyma being very thin 

 and fine. 



In the skin are numerous fragments of siliceous spicules. 



Colour. — Parenchyma pale brownish, skeletal fibres deep brown. 



Habitat.— UM-^. "Porcupine," Station 13, 1870, ofi" the coast of Portugal; depth 

 220 fathoms. 



Cacospongia dendroides, n. sp. (PI. VIII. figs. 1-3 ; PI. VI. fig. 14). 



There are in the Challenger collection three specimens, aU of a rather Spongeloid 

 shape, and from the same locality, but presenting some distinctions in the structure of 

 their skeleton, so that a subdivision at least into varieties is necessary. One of the 

 specimens is represented on PI. VIII. fig. 1, and therefore a further description of 

 its general form is superfluous. The other specimens all agree as to their external shape 

 with the one just mentioned, but while the skeleton of this latter (PI. VI. fig. 14) is 

 composed of an irregular network of comparatively thick and yeUow coloured fibres, the 

 skeletons of the two other specimens, which do not differ from the former as to the 

 general character of the network, are composed of fibres twice as thin, forming meshes 

 approximately twice as large as in the former case, and not of a yellow colour but white. 

 Is this a character of individual or of varietal, or of specific significance 1 I must confess 

 I am not prepared to decide the question, and think it advisable to choose the middle course 

 by establishing two provisional varieties — dura for the specimen with more solid fibres, and 

 friahilis for the two remaining. In both cases all the skeletal fibres proved to be more 

 or less cored with foreign enclosures. AU the three specimens have proved to be full 

 of filaments, and it was in two of them that I found out those dumb-bell -shaped corpuscles 

 to which I have referred on page 14. 



If amongst the skeletal fibres of this form the primary — vertically directed — can be 

 still distinguished owing to their comparative thickness, it must yet be added that such a 

 distinction is of a rather conditional character, the skeleton presenting the aspect of a 

 pretty irregular network. 



Colour. — Pale yellowish-white. 



Habitat.— Station 208, January 17, 1875, lat. 11° 37' N., long. 123° 31' E. ; depth 

 18 fathoms, blue mud. 



