CREATION BY EVOLUTION 



mislead. It was based on die belief diat species are fixed 

 and immutable, and its use encourages that belief. That 

 "species are species" is a statement often made in support of 

 the idea that naturalists in practice treat species as fixed. 



The circulus, on the other hand, is a natural grouping, 

 which adopts evolution as a fact and as achieved by slow 

 variation in all the members of a group in various directions. 

 Each circulus has what Bateson called a centre of organic 

 stability, and most of its members tend to be near the centre 

 so long as the condition remains the same. Wherever dur- 

 ing the growth of the Cutch Montlivaltia the sediment depos- 

 ited on the sea floor accumulated steadily, most of the corals 

 would have the same ratio of diameter to height; but if it 

 accumulated at one place more quickly than at others, the 

 centre of organic stability at that place would be with corals 

 that were higher in proportion to their width. 



The circulus provides a nomenclature which is consistent 

 with the view that evolution results from changes affecting 

 the mass of individuals belonging to a group and which 

 relieves the naturalist of worrying over, say, the number of 

 species among British brambles. Discussions of such prob- 

 lems, except in so far as they stimulate close observation, 

 are comparable in utility with the mediaeval arguments as to 

 how many angels could stand on the point of a needle. 



REFERENCES 



Bateson, W. The Study of Variation, Treated With Special Regard 

 to Discontinuity in the Origin of Species. 1894. 



Bolton, H. Insects from the Coal Measures of Commentry. 56 

 pp., 3 pi. 1925. 



Gregory, J. W. Catalogue of Fossil Bryozoa in the Department 

 of Geology, British Museum. The Jurassic Bryozoa, pp. 1, 

 22-28. 1896. Jurassic Fauna of Cutch, Vol. II, pt. 2. The 

 Corals, pp. 17-23. 1900. Palaeontologia Indica, ser. IX. 



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