426 Mr Gardiner, On the Unit of Classification 



continue to grow. Zoology as a science commenced with the 

 doctrine of evolution, a generalisation of facts. Species in the 

 older sense are not, but the meaning of the term is clear to all. 

 It is not unscientific to call each twig of our tree by a separate 

 name. In nature each twig is different from its neighbour, and 

 is many times reduplicated. Each replica varies somewhat, but 

 the main characters of the twig are repeated in all. New twigs 

 may perhaps be formed by the splitting of old twigs, but the 

 more general method — certainly in corals — is by the bursting 

 of buds. 



In conclusion I would venture to remark that Mr Bernard's 

 method of classifying forms would receive a more scientific 

 foundation, if it were built on a correlation of his forms with 

 the physical conditions of their environment, i.e. on habitat, as 

 influencing variability rather than on locality. In any case the 

 new unit appears to me to be quite unnecessary — even if scienti- 

 fically accurate (which, I consider, it is not) — and harmful, in that 

 if adopted, it would tend to obscure facts and the reasonable 

 deductions therefrom. It would prevent for all time the rearing 

 up of our superstructure on a firm foundation, and is calculated 

 to materially hinder enquiry — the offspring of speculation — into 

 the means by which our tree sprung up and grows. 



If Mr Bernard cannot satisfactorily classify his forms, I may 

 perhaps venture to point out that he has hot yet come to the 

 limits of enquiry into the structure of the Madreporaria. The 

 Porifera were formerly classified practically entirely by the form 

 of their skeleton, and the examination of their soft parts — a far 

 more difficult task — has yielded valuable results of the highest 

 scientific importance. The Hexactiniae, from which the Madre- 

 poraria are almost certainly derived, are necessarily classified 

 entirely by means of the polyp-structure. For the Madreporaria 

 the skeleton — a later and an entirely extra-mural structure, as 

 shown by Mr Bourne, whose observations I can fully confirm — 

 is alone examined. The most careful investigation of the co- 

 rallum is desirable, so as if possible to trace how far and the 

 means by which our living forms may have been evolved from 

 the fossil. Yet by this means we cannot ever hope to get more 

 than a short way back. 



Ought not rather every character, especially such as be speci- 

 fically variable, to be taken into account in systematic biology ? 

 Mr Bernard makes no attempt to put this into operation, and yet 

 admits the proposition : — " And here in passing I should like to 

 remark that I am only developing the teaching of my honoured 

 friend and teacher Prof. Ernst Haeckel, who 30 years ago in his 

 Biologie der Kalk Schwamme insisted that classification was worth- 

 less unless based upon profound morphological study. It is the 



