Davenport, Charles Benedict (November 1900) On the variation of the shell of Pecten Irradians Lamarck from Long Island. The American Naturalist, 34 (407). pp. 863-877.
Abstract
The right or lower valve of P. irradians has on the average half a groove more than the upper, because the series of alternating ridges and grooves of the right valve has a prevailing tendency to end in grooves. Of three Long Island localities, the most nearly land-surrounded shows Pectens with the greatest number of rays. The right valve is less variable than the left, a result which agrees with the fact that the right valve of Pectens is generally more archaic than the left. The variation is nearly normal in both valves; more so in the left than in the right valve. The skewness is positive, showing a slight tendency towards an excessive production of the many-rayed individuals, or the selective annihilation of those with few rays. This positive skewness is paralleled by the fact that P. irradians seems to be developing towards a larger number of rays. The various abnormalities of Pecten are either explained as self-adjustments to accidents or as sports which represent typical conditions in allied species.
| Item Type: | Paper |
|---|---|
| Subjects: | evolution |
| CSHL Authors: | |
| Communities: | Station for Experimental Evolution at Cold Spring Harbor |
| Depositing User: | Matt Covey |
| Date: | November 1900 |
| Date Deposited: | 17 Jan 2013 15:41 |
| Last Modified: | 01 Nov 2017 14:57 |
| URI: | https://repository.cshl.edu/id/eprint/26520 |
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