of the Shell of Rhynchonella Geinitziana. 307 



of the shell, — a conclusion which I have shown to be negatived by 

 the decisive test of a vertical section. 



I feel myself justified, therefore, in reiterating my former state- 

 ment, that the passages which are visible in the shell of Rhyncho- 

 nella Geinitziana traverse the internal layer only, and are there- 

 fore of the nature of pits, having no physiological relationship 

 with the canals which traverse the whole thickness of the shell of 

 the typical Terehratulida, and which open out in large trumpet- 

 shaped orifices on its external surface, although presenting such 

 a rudimental approximation to that structure — as might almost 

 be expected in some member of the imperforate series. 



The readers of the 'Annals' have now both sides of the case 

 fully before them, and can form their own judgment whether it 

 is more likely that Prof. King or that I have fallen into a " serious 

 mistake" in this matter. But I must ask them to bear in 

 mind that Prof. King's observations upon this shell have been 

 made, by his own showing, only with a Stanhope lens, upon the 

 exposed surfaces of his specimens ; whilst mine have been made 

 with a Binocular microscope and a magnifyiug-power of 120 

 diameters, upon transparent lamellae and sections. Further, I 

 would recall to their recollection that it was by surface-obser- 

 vation with the Stanhope lens that Prof. King was formerly led 

 to commit himself to the conclusion that all Brachiopod shells 

 are perforated; from which conclusion, if true, it would necessa- 

 rily follow that the elaborate drawings and descriptions which I 

 had given (in the Reports of the British Association for 1844), 

 of the microscopic structure of the non -perforated forms, had no 

 prototypes in nature*. 



University of London, Burlington House, W. 

 October 16th, 1865. 



* So far from having ever expressed his regret for this grave imputation, 

 of the fallacy of which he has had ample opportunity of convincing him- 

 self, Prof. King has recently pursued the very same course, in asserting that 

 Eozoon Canadense is not a fossil, but is a product of chemical and physical 

 agencies. For, if this be true, it necessarily follows, either (I) that my de- 

 scription of its Foraminiferal characters has no foundation in fact, or (2) 

 that I am incompetent to pronounce upon what I assert to be indubitable 

 Foraminiferal structure. As he has not adduced one single fact to justify 

 either of these charges, I have felt myself called upon to repudiate in toto 

 his claim to authority in this matter. Whether, under such circumstances, 

 the charge of " personality" is to be laid at my door or at Prof. King's, 1 

 leave it to others to decide. Although he may have used no hard words, 

 the imputations conveyed by his assertions would, if true, be more 

 damaging to my personal as well as to my scientific character than any 

 epithets he could employ. 



2V 



