43 



können." Dr. vou Lendenfeld has thus modified the opinion he 

 had some monthes ago. SoUas's membrane is no more a » Kunst- 

 product" ; his conclusion is as follows: — »Ich denke mir, dass 

 diese » Membranen" von Sollas und Dendy weiter nichts sind als 

 die Grenzen — zuflillig besonders deutlich — von jener Substanz 

 die zwischen den Kragenzellen liegt". 

 1890. Dendy, Arthur, Some old and uew Questions concerning 



Sponges. In: — Zool, Anz. Jahrg. XIII p. 14 — 17. Vide 



pp. 14 & 15. 

 The author upholds the existence of Sollas's membrane and 

 shows the impossibility of the statement of Lendenfeld that, at 

 least in Stelospongus there exists a »mesodermar' groundsubsbance 

 between the choanocytes. 

 1890. Dendy, Arthur, Studies on the Comparative Anatomy of 



Sponges. III. On the Anatomy of Grantia labyrinthica , 



Carter, and the so-ealled Family Teichonidae, In : — Quart. 



Journ. Mier. Sc. (2). Vol. XXXII p. 1-39. PI. I— IV. 



Vide p. 21—24. 

 The author now replies to Lendenfeld more fully , first of all 

 reproaching the German author his generalizing from one species 

 to a whole group. A description is then given of the condition 

 in Grantia labyrinthica. »A11 the collars and flagella of the col- 

 lared cells are retracted in my preparations. This is not to be 

 regarded as a purely artificial and post-mortem condition , but 

 probably rather as a periodically recurring phase in the life his- 



tory of the cells In this retracted condition the collared 



cells .... of Grantia labyrinthica are somewhat pyramidal bo- 

 dies , polygonal in transverse section , and with the narrow end 

 pointing towards the lumen of the chamber .... The nucleus is 

 situated in the apex of the pyramid .... Even at their bases the 

 collared cells appear to be separated from one another by distinct 

 intervals .... but these may possibly be due to shrinkage The 

 apices of the cells are still further apart, and in longitudinal 

 sections .... are seeu to be counected by a fine , sharp line 

 running from one to the other. This line is Sollas's membrane 



