of starfishes when only a single arm and a small piece of the disk have been left. Notwithstanding the small amount of living substance at their disposal, and although they are at first unable to take nourishment, they send out very small new arms (Fig. 101), close up the wounded surface, and, after reconstruction of the mouth and stomach, begin to feed anew. The new arms may then grow to the normal size. [2] I see now that there are contradictory statements in regard to this case. Possibly these depend on the different behaviour of different species, and this on the varying frequency of mutilation. Starfishes which live on the shore between the rocks, for instance on the movable stones of a breakwater, are very frequently mutilated; in some places it is rare to find a specimen without traces of former wounds. H. D. King counted among 1,914 specimens of _Asterias vulgaris_ 206 in the act of regenerating a part, that is, 10.76 per cent. In the case of the starfishes from deep water this cause of injury does not of course exist. [Illustration: FIG. 101. A starfish arm, growing four new arms; the so-called 'comet-form.' After Haeckel.] We must therefore assume that, in many cases, the regeneration-primordium consists of cells which only contain a definite complex of determinants in the form of latent regeneration-idioplasm, as, for instance, certain cells of the tail of Triton contain the determinants of the tail, certain cells of its leg the determinants of the leg, and so on. In many cases we can speak even more precisely, and determine from which cells the nerve-centres, from which the muscles, and from which the missing section of the food-canal will be formed, as was recently shown by Franz von Wagner in regard to the worm _Lumbriculus_, whose regenerative capacity is so extraordinarily high. We must then attribute to each of the relevant cells an equipment of regeneration-idioplasm, which includes only the relevant complex of determinants.