The Reactions of Planarians to Light
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1907 edition. Excerpt: ...genus and not necessarily of other species of the same genus, and, finally, into those peculiar to the individual as such, which may not in all particulars be shared by other representatives of the species to which the individual in question belongs. It is in this sense of the terms generic, specific and individual, that behavior will be taken up in the present section. A Generic and Specific Behavior In the present inquiry a basis for generic comparisons is afforded by a study of the behavior of individuals of four different genera, namely, Planaria, Dendrocoelum, Phagocata and Bdelloura, while some idea of specific differences is made possible by comparing the behavior of individuals of the two species Planaria maculata and Planaria gonocephala. In the cases of Dendrocoelum, Phagocata and Bdelloura it is obvious that the conclusions drawn are based in each instance upon the behavior of representatives of a single species under each genus. The question may be properly raised as to how far such conclusions indicate generic behavior and how far specific behavior. Conceding that from the data obtained exact deductions may not be drawn, the fact still remains that the three species, Dendrocoelum lacteum, Phagocata gracilis, and Bdelloura candida, are separated from each other by generic gaps, such that the differences exhibited by these species may be regarded as generic in degree. The point unestablished, then, is whether other species of the genera in question if examined might not show that the behavior, which in these single representative species seems generic in nature, is not characteristic of other species of the same genus as well. It will be convenient to present the data of both generic and specific behavior at the same time....
- 189 x 246 x 2mm | 95g
- 13 Sep 2013
- Illustrations, black and white