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Show 114 Utah Academy of Sciences} Arts and Letters [Vol. XV, Our longest record, No. 38, can be taken as quite typical of most the individual records for this species. To summarize, it appears that growth in this species varies tremendously with individuals even under the same conditions. Conditions that call forth sudden growth in a few members of the colony may leave others relatively little affected. p. 560). of Closely correlated with the observations on growth, were observations on the color of mantle. This snail has a distinct red banding of the shell. Whether or not there is any correlation between these bands and the color apparent in the mantle was the object of these observations. Each snail was examined under a binocular to determine whether or not a red shell-stripe or a colorless section of the shell was being formed. Observation of Apr. 20, 1932: 36 specimens. Animals active, i.e. mantle edge is in contact with the edge of the shell. Twelve red mantled snails were forming a red stripe on the shell, 1 pink mantled snail was forming a red stripe on the shell, 2 red mantled snails were so irregularly striped that it was uncertain whether the colorless stripe was being finished or the red begun. Three pink mantled shells were likewise doubtful. Of those with clear mantle, 18 were forming the colorless portion of the shell. Observation of April 27, 1932: 122 speci mens. Animals active as in the preceding observation. Of these, 56 were red mantled and were forming the red stripe, 4 pink mantled were doubtful. because of the irregularity of the shell stripes, 2 red mantled were likewise doubtful, while 60 with clear mantles were forming the colorless portion of the shell. Observation of May 25, 1932: 18 specimens. Animals for the most part with mantle detached from shell and retracted. In this case, 3 red mantled had been forming the red stripe, 3 clear mantled had been forming the red stripe before retraction, 12 clear mantled had left off shell formation while forming the colorless portion. Observation of July S, 1932: 42 speci mens. Animals active after very damp period. There were 16 red mantled forming the red stripe, 23 clear mantled were forming the colorless part of the shell, 3 red mantled were doubtful. Observations of Dec. 26-28, 1932': over 125 specimens were examined after a warm rain which aroused the snails from hibernation. Mantles were practically all clear and not attached The shells were about evenly divided as to ending to the edge of the shell. with a colorless or red stripe. These observations indicate that generally in the active animals there is a correlation between the red mantle (which secretes red mucus) and the formation of red stripes or "flame bands" by This correlation obviously is negative during the retrac the mantle collar. There should tion of the mantle within the shell for long periods of time. If true, interesting speculations be further records checking this tendency. At present it would as to the function of the red mucus would be in order. seem that this secretion of color into the mucus may be only an excretion of excess pigment. In connection with the growth of shell and color, two almost-forgotten references might be noted. The first by Hodgson (Hodgson, C. S., 1894, The rate of growth of Helices, Nautilus, Vol. 8, p. 82) records observations on the comparatively slow growth rate of the tiger snail as compared with that of Polyqyra (then Helix) appressa. The second by Ormsbee (Ormsbe, C. c., 1896. Influence of the environment upon the form and color of Heli» alter Vol. 10, pp. 63-64) attempts to. correlate the ground color nata. Nautilus, of the "tiger snail" with the type of decayed wood eaten, as: decayed maple almost black: decayed elm-dark brown; decayed ash-light brown; decayed beech-still lighter; and decayed birch-a r:eddish tinge. In .each case color stripes tended to .correspond. My observations tend. to cnflm the former article. but the latter is beyond my present field of investigation. Ormsbee. however. claims his conclusions are based on several hundred observahons. In respect to regeneration of shell. in Ayr!l and May 1932, 23 snails each obwith the lip of the aperture of the shell similarly deeply notched, were |
