QUANTITATIVE STUDY OF THE EFFECT OF ENVIRONMENT UPON THE FORMS OF NASSA OBSOLETA AND NASSA TRIVITTATA FROM COLD SPRING HARBOR, LONG ISLAND
AbstractComparing in detail the habitats of the two species, it is seen that N. obsolete lives in large numbers on flats and shores left bare by the tide during part of the day, and is not found at any considerable depth; while N. trivittata is found in some places at a depth of forty fathoms, and is not found above low water line. Verrill (73) states that about Vineyard Sound N. obsolete occurs in bays and sounds on sandy and muddy shores and bottoms, and on submerged wood-work, such as the piles of wharves, but that it does not occur on rocky shores and bottoms. If. obsolete, was found in brackish water on sand, mud, oyster-beds, eel-grass, and submerged wood-work; but it was not found in the open ocean. If. trivittate was found by Verrill in all the habitats of N. obsoleta except the muddy shores of the bays and sounds and the muddy shores and bottoms, oysterbeds and eel-grass in the brackish water; it was found in the open ocean on shores and bottoms. With these observations my own experience with the distribution of the two mollusca at Cold Spring Harbor and elsewhere is in complete accord.