( 38 ) 



to study the sponge, as far as the dry specimens allowed it, Harting 

 published in 1870 his well-known "Mémoire sur le Genre Potérion", 1 ) 

 the result of an examination of 27 specimens. Since that time the 

 sponge has hardly been mentioned. It seems indeed strange that since 

 Schlegel's publication — half a century ago — these gigantic 

 specimens which obviously were far from rare were never or 

 hardly ever sent to any of our museums, and that none of the 

 numerous expeditions of later times brought home even a single 

 specimen of Poterion. As far as I can judge even the Siboga- 

 expedition is no exception. My request to several people in our 

 colonies in the Malay Archipelago remained unanswered, till last 

 year, when I received a letter from Dr. P. N. van Kampen, assistant 

 Zool. Mus. Buitenzorg, mentioning, that in his presence three spe- 

 cimens of Poterion were dredged off Bantam at a depth of about 

 25 M. Thus the sponge was found again at last. Dr. van Kampen was 

 kind enough to send me fragments, well preserved in 96°/ alcohol ; 

 he also told me from time to time when new specimens were collected 

 all from the West part of the Java-sea. We learn from this, that 

 the sponge is not rare. 



Since nothing was known about the anatomy of the "soft parts" 

 of Poterion, I was rather anxious to study microscopical sections of 

 well-preserved specimens. It struck me at once that the structure 

 of this Poterion closely resembles that of the so-called OscuUna 

 polydomeUa O. S. of which I prepared a description and drawings 

 many years ago 3 ). 



Now this O.sculina is nothing but the "free form" of a boring 

 sponge, as first pointed out by Carter *) ; Lendenfeld afterwards 

 (1895) 4 ) proclaimed 0. polystomella as the free form of Vioa viridis 

 O.S. Independently of Lendenfeld I arrived at about the same result. 



It was, therefore, but a logical conclusion to suppose that Poterion 

 patera was likewise the free stage of a boring sponge, and I begged 

 Dr. van Kampen to look whether in the localities where Poterion 

 was dredged, shells, corals, limestone or similar substances occurred 

 which were attacked by Clionidae. Meanwhile I reexamined the 

 specimens of Poterion in the Ley den Museum. The director of the 

 Museum, Dr. F. A. Jentink was so kind as to allow me to cut 



1 ) Natuurk. Verhandel. Prov. Utr. Gen. 



2 ) MS. for Fauna and Flora of the Bay of Naples. By unforeseen events the 

 publication had to be postponed more than once. I am indeed very glad to be 

 able to say that the bulk of the MS. is ready and I hope that no serious inter- 

 ruptions will prevent me from going to press soon. 



s ) Ann. d. Mag. Nat. Hist. (4) V. 

 *) Zool. Anzeig. p. 150. 



