70 THE NAUTILUS. 



PUBLICATIONS. 



MOLLUSCA OF THE SOUTHWESTERN STATES. Ill: THE HuA- 



CHUCA MOUNTAINS, ARIZONA. IV: THE CHIRICAHUA MOUN- 

 TAINS, ARIZONA By H. A. PILSBRY and J. H. FERRISS. 

 (Proc. Acad. Nat. Sci., Phila., Nov., 1909, and Feb., 1910.) 

 In a notice of an earlier number of this series I recalled the way 

 in which the malacological riches of the arid southwest were first 

 brought prominently to light, and the astonishment they created. 

 Nowadays we have become so accustomed to hearing of new things 

 from that region, that we no longer get excited over additions to 

 Ashmunella, Sonorella or Oreohelix. If the first flush of discovery 

 has thus departed, and in a certain sense the continuation of the 

 work is almost monotonous, it must be remembered that we are ap- 

 proaching a second stage, in which the abundance of the data will 

 permit generalization not to be thought of before. Thus the import- 

 ant scientific results lie in front and not behind, and it is only through 

 minutely careful survey work, like that of Messrs. Pilsbry and 

 Ferriss, that they will ever be realized. Already these authors feel 

 justified in making the following interesting statement : 



'' The facts developed in our Arizona work lead us to doubt the 

 potency of environment as a direct agent in effecting specific differ- 

 entiation, or at least to assign to such factors a wholly subsidiary role. 

 The facts seem explicable only on the hypothesis of variations exist- 

 ing or arising in the constitution of the egg, leading to modifications 

 of the adult organism which for the greater part are indifferent as 

 affecting the well-being of the race. Such adaptation as exists would 

 apparently be due to selection. The isolation of small colonies in 

 these mountains must favor the survival of what are currently called 

 mutations occurring therein. The occasional mingling of neighbor- 

 ing colonies in which diverse variations have arisen seems to have 

 led to such heterogeneous colonies as we have described in Holospira," 



In a footnote is added : 



" We believe this to be the explanation of the diversity of colonies 

 in the polychromatic arboreal snails such as Partula and Liguus, in 

 which some colonies of a given species are homogeneous, while others 

 are heterogeneous, snails of several definite color-patterns being the 

 offspring of a single mother." 



In this connection it is interesting to compare Prof. W. L. Tower's 

 results with Mexican beetles of the genus Leptinotarsa, recently pub- 



