. Biometrika. Biometry; Biology. 26 Study of N. ohsoleta and N. trtvittata at low tidc. It was not possible to find N. trivittata in abundancc in all thrce localities, so this species was taken only fi"om 3, where the shells were washed up on the beach in considerable nunibers and easily collcctcd. Only one or two specimcns were di'edged l'roni locality 2, and no specimen has been found in the inner Fig. 1. Sketch Map of Cold Spring Harbor. (4) Qualitative comparison of the shells Jrom the different localities. If hauflfuls of N. ohsoleta from each of the thrce localities niarkcd
. Biometrika. Biometry; Biology. 26 Study of N. ohsoleta and N. trtvittata at low tidc. It was not possible to find N. trivittata in abundancc in all thrce localities, so this species was taken only fi"om 3, where the shells were washed up on the beach in considerable nunibers and easily collcctcd. Only one or two specimcns were di'edged l'roni locality 2, and no specimen has been found in the inner Fig. 1. Sketch Map of Cold Spring Harbor. (4) Qualitative comparison of the shells Jrom the different localities. If hauflfuls of N. ohsoleta from each of the thrce localities niarkcd on the map be compared a decided diffcrencc in sizc will bc at once noticcd. The shells from 3, the most exposed locality, are much the largcst. On the other band they are niiich niore nunierous in the inner harbor. In comparing N. trivittata witli N. ohsoleta it is seen that the shells of N. trivittata are not covercd with algae and are not erodcd, while the shells of N. ohsoleta are covered by algae and much eroded at tip, probably in consequence. Also lY. trivittata is almost white, whereas N. ohsoleta is blackish jnirplc, its apical angle is morc acute, and its shcll is smaller. (5) Method of measuHng. The characteristics of the shells of which it was sought to get a quantitative expression were size, shape, number of whorls, color, and roughness of surface. To ensure accuracy the dinieiisions of the shell and the angle at its apex were all measured two or three tinies. On accoiint of the length of the process or the great effect of a previous reading on the judgment. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Pearson, Karl, 1857-1936; Pearson, E. S. (Egon Sharpe), 1895-; University College, London. Biometric Laboratory. Cambridge : University Press ; New York : Macmillan Co. [distributor]
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbiology, bookyear1902
