( 40) 



of narrow and short canals which open just under the dermis into 

 wider canals of which general l} r 5 — 6 unite in a common centre. These 

 canals cause the star-like tigures, already described by Harting. Tan- 

 gential sections show this plainly ; it becomes then obvious that these 

 cortical canals sometimes ramify; but the final result is always that 

 on an average five unite into a common wider canal, at right angles 

 to the surface which runs through the rest of the cortex. It is evi- 

 dent that this latter canal corresponds to the incurrent chone l ) of 

 Tetraxonia, as sections at right angles to the surface prove. 



The incurrent chones lead into the main incurrent canals; some 

 of these, as stated above, run more or less straight on for about 

 15 — 20 mm. at right angles to the sponge surface; they then bend and 

 run in a direction almost parallel to the sponge-surface. In their course 

 they give off branches, which ramify and terminate between a 

 group of the mastichorions. These are ellipsoidal in shape and 

 open with wide apopyle into the excurrent canals, the system being 

 eurypylous. A certain number of excurrent canals flow together 

 and finally open into the main canals, mentioned above; they traverse 

 the cortex witli excurrent chones, which open by procts on the inner 

 surface of the cup. 



The soft tissue, surrounding the main canals, excurrent as well 

 as incurrent, is very remarkable. I found the same sort of tissue in 

 many sponges, but especially well developed in the so-called Osculina 

 polystomella. Lendenfeld has seen this tissue, and in his description 

 of "Papillella suberea" says 2 ): "Das hyaline Gewebe, welches die 

 Hauptkanale umgiebt .... besteht aus einer glashellen Grund- 

 substanz, in welcher zahlreiche multipolare und auch bipolare Zeilen 

 liegen, deren lange und schlanke, verzweigte Auslüufer überall mit 



1 ) Of course I use here the term chone in the sense of Sollas, and not in the 

 sense of Lendenfeld. This latter author is entirely wrong in using chone as a 

 synonym for sphincter. Sollas wrote in 1880 (Ann. & Mag. Nat. Hist. (5; v. p. 135,) : 

 "The cortex is traversed by the intermaginal cavities of Bowerbank, or, as I 

 shall term them, the "cortical funnels" or "'chonae 1 '. They consist essentially of a 

 tube divided by a sphincter into a shorter proximal and a longer distal part, the 

 "ectochone" and 'endochone" respectively". Apart from the evident lapsus that 

 in this sentence the words ecto- and endochone stand in the wrong place Sollas's 

 meaning is plain enough and this definition is generally accepted. However Lendenfeld 

 has another opinion. Thus, for instance, he writes in 1897 (Die Glavulina der 

 Adria, p. 102 — 103): "In halber Höhe der Rinde . , . . . vereinigen sich diese Sam- 



melkanale zu vertikalen Stammkanalen " And further : "Oben gauz dünn, 



verdickt sich diese schlauchförmige Einfassung des Stammkanales nach unten 



hin sehr betrachtlich und bildet proximal, in der Umgebung der erwahnten 

 Verengung, machtig verdickt einen starken Sphincter, der als eine Chone aufzufassen 

 ist". 1 do not wish to discuss the matter here at length. The quoted passages leave 

 no room for misunderstanding. 



2 ) Glavulina der Adria p. 101— 10j. 



