68 SCIENCE PROGRESS. 



kind has been carried out in many cases, both statistically 

 in the field and by cross-breeding in captivity, we have not 

 got the material even for a preliminary survey of the 

 relations between species and variety. Such work is pre- 

 eminently to be commended to collectors and systematists. 

 It is for want of it that so little progress has been made 

 with these questions. It is depressing to see how those 

 who are engaged in the business of systematic work often 

 neglect to give the essential particulars as to the variability 

 of the material submitted to them for description. That 

 such a character is "variable," or "so variable that no 

 reliance can be placed on it " is often all that we are told, 

 when in many cases with little additional trouble the number 

 of specimens exhibiting each variation could have been 

 recorded, thus greatly lightening the task of those who 

 come after. If collectors and systematists would arrange 

 their work in such a way as to bring out and not conceal 

 the objective phenomena of evolution, and if the evolution- 

 ist would appreciate that the proper way to study the relation 

 of type and variety is to take up the work at the place where 

 the systematist leaves it, we should have that partnership 

 between the two classes of naturalists for want of which 

 so much effort is wasted and progress is so slow. 



BIBLIOGRAPHY. 



(i) Allen, J. A. Bull. Amer. Mus. Nat. Hist., iv., p. 21, 1892. 



(2) Chapman, F. M. Bull. Amer. Mus. Nat. Hist., iv., p. 1, 1892. 



(3) DRESSER, H. E. Monograph of the Coraciidcs, pp. 36-37. 



(4) Edwards, W. H. Canad. Ent., xxii., p. 236, 1895. 



(5) SHARPE, R. BOWDLER. Brit. Mus. Cat. Birds, xvii., p. 13, 



1892. 



(6) Weismann, A. Studies in the Theory of Descent, 1881. 



(7) Weismann, A. Neue Versuche zum Saison-Dimorphismus d. 



Sch metterlinge, 1895. 



W. Bateson. 



