E. MAESHALLI. — TEABECUL^. 149 



likely that the spicules, during iheir growth or the rleposition 

 of new siliceous matter over their surface, are covered uniformly all 

 over by an excessively thin layer of the matrix. On the other hand, 

 the impression I have repeatedly received from the observation of 

 the larger parenchyma lia in well-colored preparations, has been 

 that these have no other coating than a layer of an irreguhirly 

 meshed trabecular network, lying in direct contact with the 

 spicular surface. It is not at all improbable that many old spicules, 

 though in situ within the bounds of the sponge- wall, are to be 

 considered as lying partially outside of the soft parts, as the 

 proslals as well as the rhaphides and the floricomes at the tips of 

 the dermal hilt-rays undoubtedly do. 



In the fresh state (2-5 hours after capture), I have ob- 

 served the trabecular substance to be either simply minutely and 

 densely granular or composed of a clear homogeneous ground-sub- 

 stance inclosing a greater or less quantity of opaque and irregular 

 grauules. The nuclei presented themselves as refractive spherules. 

 Nowhere on the surface was flagellation observed. Nor have I 

 been able, notwithstanding my special endeavors with silver- 

 nitrate and methylenblau methods, to bring out cell-outlines 

 either on or in the trabecular When carmine particles were 

 added to the fresh preparation, they stuck to the trabecular sur- 

 face with a certain degree of firmness, so that they could not 

 be moved by the water curreut produced under the cover-glass 

 by the use of a blotting-paper. Watching such preparations 

 attentively or viewing them at brief intervals under the microscope, 

 the while keeping them perfectly quiet, the attached carmine 

 particles, and no less the nuclei and the protoplasmic grauules, 

 were seen for some time slowly to change their relative positions, 

 which change was accompanied by a slight alteration in the form 



