2o6 I. IJIMA : HEXACTINELLIDA. T. 



work is marked by a minute ^vliite spot, wliich under the micros- 

 cope proves to be a floricome borne on the tip of the distal ra}'- 

 of each dermalia. The meshes are seen to be overspread with a 

 cribellate dermal membrane. 



Through the dermal latticework are distinctly visible the 

 roundish or somewhat irregular-shaped apertures of the incur- 

 rent canak, which are of various sizes under 2 mm. diameter 

 and are always rather shallow in conformity with the thinness of 

 the sponge-wall. Between the said apertures the dermal lattice- 

 work is in close contact with the parenchymal mass below. 



Amongst the latter, the trend of the coarser and more 

 peripherally situatetl parenchymal bundles is traceable from the 

 outside with sufficient distinctness. Arising from the compact 

 base of the sponge, they run irregularly upwards in oppositely 

 oblique directions, branching and uniting and loosely interweaving 

 with one another without regularity. In places the bundles are 

 fully 1 mm. thick; more usually they are much thinner. 



The gadml surface (PI. IX, fig. 2) is devoid of a covering 

 latticework. The parietal oscula are seen on this side to occupy 

 each a more or less depressed position, their iris-like membrane 

 lying on a level with the general external surfoce of the wall. 

 For the rest the ga«tral surface shows an unevenness, firstly on 

 account of numerous roundish excurrent apertures, and secondly, 

 because of the most internally situated, coarse, parenchymal 

 bundles which project in a ridge-like manner. 



Close to a parietal osculum, the excurrent canals are but xery 

 small and shallow depressions. Farther away from it, they are 

 much larger, often having a diameter of 2 or 3 mm. AVIiile 

 some are pit-like though never very deej), others are flat de- 



