37 



den Clioueu her, die erst iin Bereiche der Faserschichte das gewöhn- 

 liche Anseheii von gut abgegreuzten cylindrischen Röhreu haben". 



As to this point 1 think that but very little value is to be 

 attributed to it. Betweeu this systera of lacuuae aud the system 

 of canals deseribed in Stelletta there are sufficiënt transitions. A 

 specimen of A. cerehrum from Naples possesses hicunae , but also 

 much more distiuct contorted canals , like in *S. c/rubii. On the 

 other hand I often saw lacunae-like inhalant canals in S. grubii. 

 The difference is , I believe , a very secundary one and by no 

 means always sharply defiued. 



In a Naples-specimen of A. cerehrum I had mixed up the sa- 

 uidasters with the chiasters and dertermined it as Stelletta wa- 

 generi. A comparatively high power is necessary to distinguish 

 thera clearly one from another. 



Whether Stelletta mucronata O. S. = S. carbonaria O. S. as Maren- 

 zeller accepts I cannot make out. It may be , but S. mucronata 

 O. S. may be several other things as well. We all agree that 

 only a very few species of Schmidt can be determined without 

 autopsie of the original specimens. Now Marenzeller did uot see 

 those of S. mucronata^ and as I was enabled to study Schmidt's 

 specimen of S. carbonaria in the Naples' collection, I think it 

 wiser to take the specific name » carbonaria". Of course it is 

 not a Stelletta, but can be brought to Stryphnus of Sollas. 



Sollas *) has put Stelletta helleri O. S. to Papyrula, a genus of 

 Schmidt's erected in 1868. But Gray's Penares has priority, it 

 having been erected in 1867 especially for S. helleri O. S. If 

 really Papyrula candidata O. S. is identical with Stelletta helleri 

 O. S. as Schmidt himself hints at, and as Sollas sarcastically , 

 but quite rightly suggests , the whole name Papyrula is super- 

 fluous. Unfortunately Sollas has overlooked Gray's name, and 

 Marenzeller follows him in his error. The sponge is thus to be 

 called Penares helleri O. S. 



Utrecht, Holland. Juni 1890. 



1) Challenger Report. Tetract. p. 199. 



