This is the narrative of a scientific expedition to Western Cuba and the Colorados Reefs, with observations on the Geology, Fauna, and Flora of the region, undertaken in May and June, 1914, under the joint auspices of the Smithsonian Institution and the Cuban Government. “A genuine feast for the reader. It is a narrative replete with interest concerning the roads, mountains, trees, dwellings, the inland lakes and ponds (alive with queer fish), many species of mollusca, found along the coast; the land crabs and their curious habits,” etc.—_Louisville Courier Journal._ ALL BOOKSELLERS NEW YORK =G. P. PUTNAM’S SONS= LONDON 2 West 45th St. 24 Bedford St. NEW SHELL LISTS FREE. A new list of Philippine Land Shells covering many of the most beautiful forms at greatly reduced prices. A list of 2,000 species of shells, priced at 5 to 10 cents per species. Two lists of the finer cabinet shells, the more aristocratic forms. List of American Land Shells. Illustrated list of Philippine Shells. Further lists in preparation. I desire correspondence with collectors who wish to build up large and extensive cabinets. I have in stock over three times as many species as are covered by my lists. Collections of a strictly scientific nature purchased for cash. WALTER F. WEBB, 202 Westminster Road, ROCHESTER, N. Y. * * * * * Exchange notices not exceeding three lines will be free to subscribers as long as space will allow. * * * * * FOR EXCHANGE: Marine shells from various parts of the world, for others. Send lists. J. R. LEB. TOMLIN, 120 Hamilton Road, Reading, England. [Illustration: WASHINGTON MEETING, 1914 Bryant Walker Geo. H. Clapp T. H. Aldrich John B. Henderson H. A. Pilsbry Wm. H. Dall Paul Bartsch ] THE NAUTILUS. ═══════════════════════════════════════════════════════════════════════ VOL. XXXI. OCTOBER, 1917. NO. 2 ═══════════════════════════════════════════════════════════════════════ NOTES ON THE VARIATION OF ISCHNOCHITON CONSPICUUS CPR. BY E. P. CHACE. To the naturalist the study of variation and environment and their relation to each other is always interesting and to the conchologist who studies his shells in their natural surroundings as well as in the cabinet many things are revealed. It is not, often, however, that variation in form may be so easily traced to qualities of environment as in the following instance.