CORRESPONDENCE. 



Phylogeny and Ontogeny. 



I regret that Mr. Bather should have troubled himself to reply to me while 

 he had not access to my original paper, and while he was subject to the inevitable 

 distractions and inconveniences of travelling. Under such conditions it was 

 probably impossible for him to avoid inadvertent misrepresentation. 



I did not " deny that the past history of its race has any influence on the growth- 

 stages of an individual," but only "that the phylogeny can so control the ontogeny 

 as to make the latter into a record of the former — even into an imperfect record of 

 it." This, however, is probably what Mr. Bather meant. But there is a very real 

 misrepresentation two or three sentences further down on the same page (238). I 

 have never "maintained that the development of any [ = every] individual was a 

 regular progress from the embryo to the adult." Not only am I pretty familiar 

 with Weismann's work on the Diptera, but I have myself worked out in some detail the 

 development of Culcx, in which the alimentary, respiratory, muscular, and nervous 

 systems and, to a smaller extent, other systems and organs also, exhibit phenomena 

 (histolysis, for instance) which could not by any stretch of the imagination be called 

 " regular progress from embryo to adult." The phenomenon called " metamorphosis" 

 is too familiar for any zoologist to make any such statement as that ascribed to me. 



1 have already answered Mr. Bather's question elsewhere, but as he says " it is 

 needless to reply " to my " other remarks while the above question remains un- 

 answered," I will answer it again ; merely premising that he has so far not replied 

 to any of my " remarks " on the subject under consideration, but only to " remarks " 

 which he has mistakenly ascribed to me. 



His question is this: — "What cause can have produced these deviations of 

 ontogeny from the path of simple development ? " the deviations in question being 

 those which he described in Natural Science, vol. ii., pp. 275 et seqq. My answer 

 is that the species have so varied under the guidance of Natural Selection that the 

 later stages of development have come to differ more widely from the corresponding 

 stages of the ancestors than the early stages have come to differ from the corresponding 

 stages of the same ancestors. The vestiges — I fully admit that they are vestiges — 

 still to be found in the embryos of the existing species in the case of Antedon, are 

 surviving remnants of the rudiments which existed in the ancestral embryos. They 

 are so modified that, though still recognisable, they do not now any longer follow 

 the same course of development as they did in those ancestors. Mr. Bather will 

 remember that this explanation was given with reference to the "gill-arches" of 

 embryonic birds and mammals (vol. ii., p. 198). 



As the Philosopliical Transactions and the Annals and Magazine of Natural History are 

 practically inaccessible to a large proportion of the readers of Natural Science, I 

 will again express the hope that Mr. Bather will take an early opportunity of putting 

 the more interesting and tangible results obtained by Dr. Carpenter and himself 

 before those readers, with such figures as may put them beyond the possibility of being 

 misunderstood. (Cf. Mr. Smith Woodward's article on " The Fore-runners of the 

 Back-boned Animals, 4 ' vol. i., p. 596). I feel sure that by so doing he will facilitate 

 the solution of our present problem. 



C. Herbert Hurst. 

 Manchester, Sept. 10, 1893. 



[We shall welcome any such concise statement of facts as is suggested by 

 Dr. Hurst ; otherwise this correspondence must now cease. — Ed.j 



