E. MAKSHALLT. FLAGELLATED CHAMBER. 143 



F. E. Schulze ('99 a, 19'«) of the same in Schaudinnia arctica. 



Firstly, as to the open or closed nature of the generality of 

 the meshes in the reticular membrane. According to Schulze 

 they should be closed in Schaudinnia arctica, as he originally 

 believed them to be likewise in Eupl. aspergillimi and in several 

 other species ('80, '87), though not in the same way. His 

 original conception seems to have been that the choanocytes lay 

 apart from one another but were joined together by band-like 

 connecting bridges and were disposed in a layer over and upon 

 a continuous basal membrane, much in the same manner as is 

 observed in other classes of the Spongida. His histological 

 study of Schaudinnia arctica, however, led him to the belief tliat 

 such a basal membrane, or in fact any membrane which might 

 delimit the chamber-wall from the incurrent lacun?e did not exist 

 (see p. 137) ; and he thus may be said to have come very near 

 to recognizing what I consider to be the fact, viz., the open state 

 of all the meshes of the reticular membrane. 



Schulze however entertained quite a different view of the 

 matter ('99a, p. 201 ; 19'«, p. 98). The choanocyte is described 

 by him as having a thin basal expansion — a ' fussplattenartige 

 Ausbreitung des Basaltheiles der Zelle' — which should join with 

 the same of the neighboring choanocytes and form a continuous 

 membrane, called the * Basalplatte.' This should be traversed 

 by the branching and anastomosing granular bauds which radiate 

 from around the nuclei and bring about the reticular pattern 

 visible when looked at on the surface. I make bold to say that 

 the existence of such a * Basalplatte ' is to me exceedingly doubt- 

 ful, but it would be well to leave this moot point to be 

 decided by the results of further investigations. 



Secondly, as to the prosopyles. Schulze ('80, '87, '99 a, 



