J. G. WALLER ON CLTONA CELATA, ECT. 263 



dwells in these cavities, the character of a parasite ? Parasitic 

 Sponges abound. Clefts of rocks, deserted polypidoms, shells, &c., 

 all present examples ; in fact, I here show you a drawing from an 

 instance of this very Sponge, the Cliona, taken from the same oyster- 

 shell, which has afforded me material for my observations, where it 

 appears, not in the burrows, but on the outside upon the deserted 

 home of a Lepralia, which was partially covered by the tubes of 

 SahellcR. This, of itself, suggests the habit to be parasitic, which is 

 confirmed in a still stronger manner by Dr. Bowerbank, (" Brit. Spon- 

 giadae," Vol. ii., p. 217). And I have many examples of it inhabiting 

 the deserted tubes of SerpulcB. The difficulties indeed are with 

 those who have committed themselves to the opposite view. We 

 know of no Sponge excavator except in theory.* Sponges afford no 

 sort of analogy with themselves of any such aggressive power, even 

 in those which might seem to present more external signs of such a 

 capability. 



I have endeavoured to show you, that the solution of the question 

 is, and must be, in the mode of working the burrows. The markings, 

 I have attempted to describe, can be demonstrated to be made by a 

 hard tool working in the segment of a circle, to which I have drawn 

 your attention, as shown by the Scolytiis. And that such should be 

 mimicked by a Sponge, a creature so far down in the scale, would be, 

 if proved, one of the most extraordinary marvels in natural history. 

 It would be altogether without parallel, and it therefore requires the 

 most absolute proofs before it should be accepted. No imaginative 

 dream, no assumption, no jumping to conclusions, because minor 

 points are not understood, can support such a theory in the face of 

 hard and tangible facts, in full agreement with well-known 

 precedents. 



My friend, Mr. Priest, kindly brought me for inspection the 

 specimen from New Zealand, of the excavated shell of Haliotis, 

 in the possession of Mr. Kitton, which formed the subject of 

 a diagram illustrating his paper on Sponges. On giving it an 

 attentive examination, I found the main facts differed in no way 

 from those familiar to me. The same mode of working was 

 indicated, and I saw nothing in this example, which either 

 raised or removed a difficulty.! 



* I here distinctly assert that there is no record of any observation 

 which -provesihe Sponge to be an excavator. 



t Since writing the above, I have, tiirough the kindness of Mr. Priest, been 

 enabled to quietly examine the slide in question. It has some curious 



