348 REVISION OF THE MONAXONID SPONGES, ii., 



Lendenfeld introduces the new genus Stylotella. The Stylo- 

 tellince are defined as H eterorrhaphidce without differentiated 

 microsclera, and without a hard spicular rind ; and Stylotella 

 is stated to have as its distinguishing characters: (i.) a very 

 soft texture, and (ii.) megasclera in the form of styli, scatter- 

 ed and in bundles. Of the four species I am able to identify, 

 with certainty, only two, *S'. digltata and S. 'polymastia. The 

 latter of these proves to belong to the genus Ciocalypfa (or 

 perhaps to Leucophloeus) ; while the former, which was the 

 first to be described and which I propose to regard as the type- 

 species, is found to be identical with the earlier described 

 Hymeniacidon agminata Ridley(33). This species, however, 

 as will be seen from the description given below, differs con- 

 siderably from typical species of Jlymeniacidon, and undoubt- 

 edly requires to be placed elsewhere ; for its reception the 

 genus Stylotella may therefore be retained, with the following 

 definition: — "Typically non-massive Suberitidae( ?), of compa- 

 ratively soft consistency, with a well-defined dermal mem- 

 brane which is provided with tangentially placed spicules and 

 is underlain by subdermal spaces, and with a main skeleton 

 composed of longitudinal spicule-fibres (devoid of spongin) and 

 of scattered spicules. The spicules are typically of a single 

 kind, styli or subtylostyli ; microscleres are absent." 



The genus, which is of doubtful systematic position, I refer 

 to the Sub er it idee chiefly on account of the character of the 

 skeleton, and the seemingly greater difficulty of justifying its 

 inclusion in any other family. The serious objection to this 

 is, of course, the absence of tylostylote spicules ; but as regards 

 the other features in which it departs from typical Suheritidce 

 it may be pointed out that the possession of a dermal mem- 

 brane is characteristic of P send o sub erites and Caulospongia 

 (^= Plectodendron) , and that most species of Semisub erites and 

 Laxosub erites are of soft consistency. 



Lendenfeld's Stylotella aplysillioides appears, from its de- 

 scription, to belong to Hymeniacidon; and his fourth species, 

 S. rigida, I regard (provisionally) as a synonym of S. agminata. 



