. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. Figure 1. Aperture shape in 7rioc/ops/s. 1, Auricuiate; 2, square; 3, trapezoid; 4, triangular; 5, oval; 6, circular. suits obtained evaluated statistically. The distribution and ecology were then studied by plotting the records on large scale maps showing hydrography, vegetation, and ele- vation. Information on the distribution and ecology were also taken from the literature. In the last step, the data ob- tained from these various sources were svnthesi/ed. Many of the terms used in this paper occur commonly in the l
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. Figure 1. Aperture shape in 7rioc/ops/s. 1, Auricuiate; 2, square; 3, trapezoid; 4, triangular; 5, oval; 6, circular. suits obtained evaluated statistically. The distribution and ecology were then studied by plotting the records on large scale maps showing hydrography, vegetation, and ele- vation. Information on the distribution and ecology were also taken from the literature. In the last step, the data ob- tained from these various sources were svnthesi/ed. Many of the terms used in this paper occur commonly in the literature, but some do not. Definitions of the necessary terms follow. Apeiiiue: the margin of the shell that surrounds the opening of the shell; also the surrounded area. The shape of the aper- ture may be auricular, square, trapezoid, triangular, oval, roimd, or intermediate be- tween any of these (Fig. I). These geo- metrical forms are actually never "com- plete," in the sense that the upper left corner is always truncated by the penulti- mate whorl. The term aperture is inter- changeable with lip or peristome. Aperture ^radc: the degree of develop- ment of the lip swelling, lip teeth and pari- etal lamella. Armature: llic lip teeth and the parietal lamella together. Axis: the line drawn llirough the apex and the umbilicus ol llie shell. Bifid: cleft into two lobes, , a lip tooth. Dislied: concave, , an aperture ha\- ing the lip swelling and the lij) Iceth slanted inward. Emhnjonie aiiorls: the first whorls of the shell, produced by the em- bryo inside the egg. Fulcrum: the callosity inside the last whorl, on the inner wall. Granule: the small protuberance on the surface of the shell, which does not bear a hair. This term may be used synonymously with papilla; the latter, however, may bear a periostracal hair. Ileiiiht: the vertical distance between the lowest point of the aperture and the apex of the shell, measured with the axis held perpendicular
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Keywords: ., bookauthorharvarduniversity, bookcentury1900, booksubjectzoology
