112 THE CANADIAN NATURALIST. [April 



the very extraordinary fossil which you have brought from the 

 Laurentian rocks of Canada,* enables me most unhesitatingly to 

 confirm the sagacious determination of Dr. Dawson as to its Rhi- 

 zopod characters and Foraminiferal affinities, and at the same 

 time furnishes new evidence of no small value in support of that 

 determination. In this examination I have had the advantage of 

 a series of sections of the fossil much superior to those submitted 

 to Dr. Dawson ; and also of a large series of decalcified specimens, 

 of which Dr. Dawson had only the opportunity of seeing a few ex- 

 amples after his memoir had been written. These last are pecu- 

 liarly instructive ; since in consequence of the complete infiltration 

 of the chambers and canals, originally occupied by the sarcode- 

 body of the animal, by mineral matter insoluble in dilute nitric 

 acid, the removal of the calcareous shell brings into view not only 

 the internal casts of the chambers, but also casts of the interior of 

 the ' canal-system ' of the ' intermediate ' or ' supplemental skele- 

 ton,' and even casts of the interior of the very fine parallel tubuli 

 which traverse the proper walls of the chambers. And, as I have 

 remarked elsewhere,*)" " such casts place before us far more exact 

 representations of the configuration of the animal body, and of the 

 connexions of its different parts, than we could obtain even from 

 living specimens by dissolving away their shells with acid; its 

 several portions being disposed to heap themselves together in a 

 mass when they lose the support of the calcareous skeleton." 



The additional opportunities I have thus enjoyed will be found, 

 I believe, to account satisfactorily for the differences to be observed 

 between Dr. Dawson's account of the Eozobn and my own. Had 

 I been obliged to form my conclusions respecting its structure 

 only from the specimens submitted to Dr. Dawson, I should very 

 probably have seen no reason for any but the most complete 

 accordance with his description : while if Dr. Dawson had 

 enjoyed the advantage of examining the entire series of prepara- 

 tions which have come under my own observation, I feel confident 

 that he would have anticipated the corrections and additions which 

 I now offer. 



* The specimens submitted to Dr. Carpenter were taken from a block 

 of Eozoon rock, obtained in the Petite Nation Seigniory, too late to afford 

 Dr. Dawson an opportunity of examination. They are from the same 

 horizon as the Grenville specimens. — W. E. L. 



f Introduction to the Study of the Foraminifera, p. 10. 



