22 Mr. H. J. Carter on the Relationship 



tanks close to my door at Bombay, and as a practical and 

 experimental observer, for the last two years, on the marine 

 sponges, both siliceous and calcareous, also in their living 

 state, I think it might be assumed at least that, both by early 

 education and subsequent opportunities, I ought to be qualified 

 to give an opinion in this matter. 



Now, for the most part, all marine sponges (save the Clio" 

 nidce, which may be in deciduous shells) begin to perish within 

 forty-eight hours after they have been taken from their natural 

 habitat, although their attachment to the piece of rock on 

 which they may be growing remains uninjured ; and even if 

 they survive a little this period, they are voraciously devoured 

 by the crustaceans which may be confined with them — -just as 

 in all similar and serial microscopical inquiries, whether free 

 or confined, the minute crustaceans are thus the most defeating 

 agents. With the putridity or dissolution of the sponge comes 

 a development of infusoria ; and if, under such circumstances, 

 one Vibrio is seen to pass across the field, the microscopist 

 may as well give up all further research into the phenomena 

 of the living sponge. 



On the other hand, if the seed-like body be taken from a 

 living piece of Spongilla and placed in a watch-glass with water, 

 it may be kept under a quarter-of-an-inch compound power 

 until the young Spongilla issuing from it has gone through all 

 its phases of development from its first appearance to its full com- 

 pletion, which may be seen both elementarily and collectively ; 

 while during this time, having a plurality of seed-like bodies 

 growing in different watch-glasses, the experiment of feeding 

 the young Spongilla with carmine or indigo, which soon points 

 out, by its colom-, the position and grouping of the sponge- 

 cells, together with the passage of the particles in through the 

 pores of the dermal sarcode, thence to the ampullaceous sacs, 

 and then the discharge of the ingesta through the excretory 

 canal-system — all may be deliberately watched under the 

 same microscopic power, with so little difficulty and yet so 

 accurately that there is no merit whatever in recording ob- 

 servations of the whole process. It was in this way that I 

 obtained the data published in my paper " On the Ultimate 

 Structure of Spongilla,'''' confirmed by similar observations on 

 large pieces of Spongilla taken directly from the tank ; and to 

 this paper I must refer the reader for all further information 

 on the subject. 



Latterly I have had nothing but the marine sponges to 

 examine and experimentalize on, especially the calcareous 

 ones ; and I cannot help thinking that if Prof. Hackel had 

 had the same opportunities that I have had of studying the 



