ON THE OCCURRENCE OF FLESH-SPICULES IN 

 SPONGES. 



By R. von Lendenfeld, Ph.D. 



Siliceous spicules occur in Sponges either in the ground-substance 

 or in the horny fibres or in both places in the same sponge. As I 

 have pointed out in previous papers, such Flesh-spicules may 

 aggregate to produce hard siliceous skeletons if no other skeleton 

 was] present at the time of their formation, but they remain 

 loose and small if such a skeleton was present at that time. The 

 cases where Flesh-spicules occur in the ground substance, and other 

 differently shaped and closely packed monactinellid siliceous 

 bodies form a fibrous reticulate skeleton, are numerous. These 

 Flesh-spicules are rare in other Sponges than such, which possess 

 a fibrous reticulate skeleton composed of closely packed siliceous 

 spicules. 



Only in a few Gumminse star-shaped or globular siliceous bodies 

 were known to occur, independantly of a silico-fibrous skeletor. 

 These are, however, of a very different shape from those which 

 are found in the Desmacidonidae. The latter never were observed 

 without a silico-fibred skeleton. 



I however, discovered one exception to this in a Sponge from 

 Port Phillip, as fonnerly no such exception was known. O. 

 Schmidt, "Vosmaer, and others were perfectly right to combine all 

 these Sponges with monactinelled spicules in bundles, and Flesh- 

 spicules of very varying shape to one Family, the Desmacidonida;. 

 The Desmacidonidpe are Sponges with fibres composed of monacti- 

 nellid spicules as the ChalinidaB and others, which are distinguished 

 from these latter Families by the possession of Flesh spicules. 



On the ground of this exception mentioned above, where I 

 found a Hircinia containing Flesh-spicules, I based the Hypothesis 

 that such Flesh-spicules are of no great systematic value and may 

 occur in any Family of Sponges. 

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