41(S Dr. W. B. Carpenter on Ottu Ilahns 



edition of my ' AJicroscope and its Revelations,' publislied as 

 far back as 1868 ; and has not noticed eitlier the " New- 

 Observations " which I published in the 'Annals of Natural 

 History' two years ago (June 1874), or the reproduction of 

 them contained in the fifth edition of my ' Microscope,' pub- 

 lished nearly a year and a half since. Dr. Dawson's still more 

 recent ' Dawn of Life ' of course receives no notice. 



Hence the structural facts which I hold to be all but demon- 

 strative of the Organic origin of the calcareous layers of the 

 Ophicalcite of Canada are altogether ignored in Dr. Halm's 

 discussion. Of these facts I shall recall two : — (1) the exist- 

 ence, in the best-preserved specimens, of a calcareous layer 

 immediately surrounding the chamber-cavities, which sliows 

 a parallel nummidine tubulation (not filled up by serpentine in- 

 filtration) as distinct as that of any recent NummuUte ; and 

 (2) the existence of a relation betiveen the canal-system and 

 the chamher-cavities, through the medium of this layer, so 

 precisely resemhling that wdiich obtains in Calcarina^ that its 

 peculiarity constitutes a most significant indication of Forami- 

 niferal structure. Now as I described this very relation more 

 than ten years ago * on the basis of decalcified specimens, 

 though it was only in 1874 that my reexamination of the 

 large series of transparent sections in my possession gave me 

 the additional evidence of it which I described and figured in 

 my '' New Observations," I cannot but feel surprised that 

 Dr. Hahn should assert (p. 271) not only that the canal- 

 systems " are never continued into tlie chambers," but that 

 they " have no relation at all to these," — the precise contrary 

 of the latter statement being the fact. 



2. The gist of Dr. Plahn's paper, so far as I understand it, 

 lies in the affirmation that all the appearances seen in the spe- 

 cimens Avhich he lias himself examined are not merely expli- 

 cable on the hypothesis of purely Mineral agency, but are 

 incapable of being otherwise accounted for. This argument 

 I had thus answered by anticipation in my " New Observa- 

 tions " {loc. cit. p. 469) : — " My contention is, therefore, that 

 the hypothesis of the Foraminiferal origin of Eozoon canadense 

 entirely accords with the features alike of the general and of 

 the minute structure of the best-preserved specimens of this 

 body, and that it is the only hypothesis which fits all the facts 

 of the case ; whilst the hypothesis of subsequent metamor- 

 phic change, which has every probability to recommend it, fully 

 accounts for all the appearances on wdiich the Anti-Eozoonists 

 rely as evidence of its Mineral origin." The evidence adduced 



• Proc. of Geol. Soc. Jan, 10, ISGG, p. -222. 



