ABSTRACT
Injury due to waste of materials involves injury to kindred as well as injury to self. Even more widespread is injury to kind through the universal tendency to excessive reproduction. More direct and hence more easily recognizable forms of injury to kind are found in various cannibalistic activities. Cannibalism practiced by mammalian mothers and fathers upon their own offspring is familiar for many species. Akin to the injuries inflicted by members of mammalian species upon one another, already noticed, is the well known treatment dealt out to weak or injured members of a herd of cattle by the able members. Beginning with arthropods, the authors provide a description of unmistakable death-dealing injury to kindred among spiders. Passing to injury to kind among vertebrates, they notice a few instances among the lower orders, the wholly aquatic fishes and the semiaquatic amphibians.
