212 



PROCEEDINGS OF THE ACADEMY OF 



[Mch., 



upon in the discussion of the composite nature of snail colonies (p. 226), 

 since the conclusions reached from molluscan studies apply equally to 

 communities of other comparatively sedentary animals. 



Throughout the preparation of this paper I have had the coopcra- 



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rOOTHlLLi III 



Sketch of Huachuca range, by J. H. Ferriss. 



tion of Mr. J. H. Ferriss. I would also gratefully acknowledge assist- 

 ance lent by Dr. Wm. H. Dall, in the comparison of various species 

 of Holospira, etc., with those described by him. 



The figures of shells were photographed and those of soft anatomy 

 drawn by the author. 



