HARDWICKE'S SCIENCE-GOSSIP. 



73 



THE COLOUR AND BANDING IN LAND AND FRESH- 

 WATER SHELLS: A REPLY TO MR. FRYER. 



By J. W. WILLIAMS. 



IXCE forwarding for 

 publication my 

 reply to Mr. Pace's 

 strictures on my 

 article which was 

 printed in the 

 August number, 

 ?vlr. Fryer has, on 

 pp. 241 and 242 

 ante, published a 

 very interesting 

 and courteous cri- 

 ticism to which I 

 may be allowed to 

 reply. His open- 

 ing remarks to a 

 large extent I ap- 

 preciate, but as 

 shown by my con- 

 cluding remarks of 

 the article in ques- 

 tion I gave the theory as a tentative one only, 

 and certainly it will be conceded that no matter 

 what our present knowledge may be, yet the pro- 

 mulgation of a theory on such grounds, and as a 

 working one merely, is perfectly legitimate. There 

 would be no harm done even if with further re- 

 search it led to no good and stable result ; for it 

 certainly would not allow us to vegetate, AVith the 

 qualification to Von Baer's law (italicised by Mr. 

 Fryer), I do not agree, simply because it is a well- 

 known fact and law that no matter whether retro- 

 gression has occurred or not in our present day forms, 

 evolution has progressed primarily along a line 

 leading from the simple to the complex. My critic 

 says that if this is what I intend to ' ' convey, it 

 certainly does not accord with the views of evolution 

 as laid down by Darwin, Wallace, and Spencer ; " 

 but this statement is plainly negatived by the fact 

 that Mr. Wallace [in lift. September 7, 1 890), agrees 

 No. 316. — April 1891. 



with my conclusions. Throughout Mr. Fryer does 

 not seem to attack the main points in my theory, and 

 our greatest difference seems to me to be this : — that 

 he does not recognise the fundamental law of Hxckel, 

 while I do. 



This appears to me a pity, because while recog- 

 nising to some degree Yon Baer's law, he appears 

 to totally set at naught the very law, on the principle 

 of which the grandest contributions of embryologj' 

 and palaeontology have been furnished to the hypo- 

 thesis of evolution, viz., that " Ontogeny is a brief 

 epitome of phylogeny." And even more does it 

 appear a pity since the majority of our biological 

 teachers in this countiy give it as forming the ground- 

 work, with that of Von Baer, on which the whole 

 superstructure of the evolution hypothesis has been 

 raised. In my reply to his several headings, I shall 

 then count on the validity of these two laws, and I 

 imagine legitimately in the present day teaching of 

 science. 



(i.) This sentence seems to me somewhat 

 ambiguous, for to me Mr. Fryer appears to directly 

 contradict himself in one breath. He uses the words 

 " chitinous plug," and afterwards speaks of it as 

 composed of " conchiolin, not chitin." I have 

 replied to this criticism in my former note on Mr. 

 Pace's strictures, and made reference to Balfour. I 

 cannot see how it invalidates my theory if I believe 

 in Hceckel's law. 



(2 and 5.) The nuclei of my specimens of H. 

 virgata are brownish horn-coloured, and not black. 

 Possibly, there is a fallacy here ; if a little of the 

 digestive gland be left behind in cleaning, the nuclei 

 may appear black. But even were it so, it would 

 not negative the general conclusion to which I arrived, 

 simply because it may but prove an after-extension or 

 development of colour. That there is a law of 

 extension of colour appears to me proved by the 

 following sentence quoted from Eimer : — " WUrtem- 

 berger finds that in Ammonites all structural changes 



