Structure of Eozoon canadense. 283 



canal-system originates, not directly from the chambers, but, 

 as in Calcarina, from a set of sinuses outside the tubulated 

 chamber-wall. Now Mr. Carter seems to suppose that Dr. 

 Dawson, and all those who agree with him in this identifi- 

 cation (which Dr. Dawson first made by comparison with 

 specimens of Calcarina he had received from myself), have 

 been so " green " as never to have thought of the probability 

 that the so-called canal-system may be nothing else than 

 dendrites of glauconite. This hypothesis has from the first 

 been present to our minds, as Mr. Carter would have seen if 

 he had read the memoirs which he has thought fit to ignore. 

 And, not to mention other reasons, I may state two, which 

 perfectly satisfy Mr. Sorby (the most eminent authority on 

 micro-mineralogy) that they cannot be thus accounted for. 

 Fu-st, these dendrites usually pass directly across the cleavage- 

 planes of the calcareous shell, between which, if they were 

 infiltrations, they would be almost certain to spread. Second 

 (and this is, to my mind, still more conclusive), that minuter 

 part of the canalicular system which is only to be discerned 

 in the very transparent calcite by a careful management of the 

 light (and which Mr. Carter has obviously not recognized), is 

 not injiltrated loith any foreign mineral at all; but is simply 

 filled up with calcite, disposed in the same crystalline axis 

 with that of the shell itself, as is the case in the consolidated 

 calcareous network of the fossil spines of Echinida, the stems 

 of Crinoidea, and the like. An experience of thirty-five 

 years, extending over a wide range of Micro-paleeontological 

 inquiry, has given me, I venture to think, some special apti- 

 tude for recognizing Organic structure when I see it ; and I 

 never saw, in any fossil whatever, more distinct evidences of 

 organic structure, than are to be seen in these finer ramifica- 

 tions of the canal-system oi Eozoon j which are far more distinct 

 than is the tubulation of any but the best-preserved fossil 

 Nummulites. 



I do not pretend to affirm that the doctrine of the Forami- 

 niferal nature of Eozoon can be proved in the demonstrative 

 sense. But I do affirm that the convergence of a number of 

 separate and independent probahilities^ all accordant with that 

 hypothesis, while a separate explanation must be invented for 

 each of them on any other hypothesis, gives it that high pro- 

 hahility on which we rest in the ordinary affairs of life, in the 

 verdicts of juries, and in the interpretation of Geological 

 phenomena generally. 



To any one who calls in question the evidentiaiy facts I 

 have adduced, I simply say " Come and see." I cannot be 



