344 REVISION OF THE MONAXONID SPONGES, ii., 



of interconnection; and, in part, (ii.) of an irregular reticu- 

 lation composed of thin pale-coloured horny fibres and of 

 somewhat disorderly disposed spicules which for the most part 

 are not enclosed within the horny fibres, but merely held to- 

 gether by them. The funes, also, are composed of reticulating 

 horny fibres and spicules, but in them the meshes of the reti- 

 culation are much smaller and the spicules are much more 

 uniformly oriented, the latter being in general not widely in- 

 clined from the longitudinal direction of the particular fune 

 containing them ; the funes are rendered plumose by the 

 obliquely outward inclination of their most exteriorly situated 

 spicules, some of which give rise to occasional short wispy 

 strands. 



In the single thick section^ examined by me, these two types 

 of skeleton-pattern — axinellid in the one case, somewhat 

 approaching to halichondroid in the other — occur for the most 

 part separately from each other. Thus, on the one side of a 

 primary fune, which approximately coincides (probably mere- 

 ly by chance) with the mid-line of the section, the pattern is 

 mainly of the former type ; while on the opposite side of it, the 

 pattern is mainly of the latter or more halichondroid type. 

 The structure of the funes is such, however, that they might 

 be interpreted simply as more condensed portions of the skele- 

 ton, in which at the same time the spicules tend towards a dis- 

 position in a common direction. 



There is no dermal skeleton ; and, furthermore, in a superfi- 

 cial layer of the sponge, varying from about 150 to 600 /x or so 

 iu width, no spicules occur except those composing the (some- 

 what distantly separated) extremities of the outwardly run- 

 ning fibres. As regards its histology, this layer (as seen in a 



* In thin sections, as may easily be understood, the funes do not appear 

 as such; and as a consequence, the arrangement of the skeleton seems to 

 be rather confused. At first, having only examined such sections, I was 

 disposed to regard as fairl}' satisfactory Lendenfeld's statement that " the 

 skeleton consists of bundles of loosely disposed spicules, which are con- 

 nected by verj' numerous others, scattered in such a way that the whole 

 often appears like a dense mass of irregularly disposed spicules." 



