254 



WALLER ON CLIONA CELATA. ETC. 



single one terminates in a round or oval cavity, varying in its 

 diameter from three to eight or nine times the diameter of the tube ; 

 up some of tliese tubes the Sponge may be seen lowly winding its 

 way, with one or two spicula disposed in a longitudinal direction, 

 while the upper portion of the tube and the large terminal cavity is 

 completely empty.* In another part of the same specimen there is 

 one of these large elongo-oval cavities, from which there are four 

 ccBCoid canals, radiating from it^ of different lengths, two long and 

 two short ; the cavity is entirely filled with the Sponge, apparently 

 from a fifth canal connected with the exterior of the shell. Now 

 the condition of the Sponge in the four ccecoid canals is relatively 

 the same, that is to say, all the parts in immediate proximity to the 

 large cell are filled with the Sponge ; the two small ones entirely so, 

 the two long ones partially so ; the shortest of the two long ones, 

 for rather exceeding one -third of its length, and the longest for not 

 more than one-fourth of its length. This condition of the Sponge 

 in relation to the shell, unmistakably indicates that the cavities and 

 canals were prepared previously, and that the Sponge, at the time 

 that life was arrested, was slowly winning its way into them." 



Now let me arrest you here for a moment, whilst we consider the 

 bearing of these passages on the question before us. Dr. Bower- 

 bank, though, like everyone else, he made his mistakes, yet is acknow- 

 ledged, even by his most inveterate antagonists, to have been a most 

 excellent observer. And the question before us is one of observa- 

 tion. He tells us what he saw, not what he imagined. He tells us 

 tliese borings are sometimes empty, sometimes only partly occupied 

 by the Sponge, which is still growing and progressing in the excava- 

 tion. Nor can his testimony be easily set aside. A long life spent 

 in the pursuit of natural history, and notably in this department, 

 carries with it special claims. To say he could not see, nor describe 

 what he saw, would be boldness indeed. But you must dispose of 

 what he says or accept all it involves. His high character forbids 

 us to say he does not tell the truth, and to leave what he says 

 unanswered is impossible. It is a dilemma ; but the case does not 

 rest on this, nor have I yet done with all the evidence he gives. If 

 the facts are admitted, a new theory will be required for the '' boring 

 Sponge " not being in the channel excavated, the more especially 

 will this be necessary when the Sponge is found in one part of the 



* There is the same evidence given in PI. XXI, Fig. 1, also at Fig. 5, and 

 abundantly in the section vpheuce this was taken. 



