EVOLUTION 1005 



peculiarities in environment, nutrition, and habits. The suggestion 

 cannot be taken very seriously until it is made the subject of critical 

 and sceptical experiment. Yet the idea should be kept in mind; there 

 are many suggestive facts. Thus we have seen two "species" of 

 Alcyonarians, distinct as regards structure of spicules and individual 

 polyps, growing as members of one and the same arborescent 

 colon3^ where the conditions are necessarily not quite uniform 

 throughout. In many cases, throughout the animal and vegetable 

 kingdoms, a particular species habitually develops and lives in a 

 specific environment, which perhaps evokes or, it may be, indents 

 particular structural features. Development in a novel environment 

 ma}' in some cases, as in sponges, result in the appearance of very 

 atypical characters, which may be interpreted as somatic modifica- 

 tions. Giard called this "poecilogony". 



Now the question rises whether some of the specific characters 

 which we unhesitatingly regard as intrinsically diagnostic of a species 

 ma\7 not be simply somatic modifications, reappearing generation 

 after generation because uniformlj^ reimpressed, yet never as such 

 forming an integral part of the germinal inheritance. 



Labbe has made some interesting observations on certain small 

 crustaceans (Canthocamptus) living on the Salines of Croisic. He 

 found that increased hydrogen ion concentration affected the 

 progeny in such a way that it included several species! Thus eggs in 

 the ovisacs of specimens of Canthocamptus minutus, exposed in a 

 new medium, developed partly into typical forms, and partly into 

 three other species, one of them new! The non-typical forms he calls 

 "allomorphs". This interesting conclusion has received valuable 

 taxonomic criticism from an expert, Mr. Robert Gurney, who also 

 points out the great risk of the accidental inclusion of the minute 

 larvae of other species. Nevertheless, it is an idea worth watching ! 



VARIATION AND HEREDITY 



Yet a further word on Variation in relation to Heredity; 

 which have generall}^ been, and still very commonly are, too 

 sharply contrasted. So far, no doubt, these seem antithetic: but 

 we must remember Hegel's law — that no antithesis finds simple 

 and final synthesis, but rather two counter-syntheses, and so far 

 antithetic still, yet complemental too. So in this case, and on one 

 side, variable Heredity, for which the Mendelians have made room; 

 and on the other side hereditary Variability, as in De Vries's con- 

 spicuous many and new variations amid his (Enothera sowings. 

 No doubt heredity has been accumulating its brake-power on varia- 

 tion throughout a long past; much as we see in the powerfully 



