Can any one imagine the existence of a being with only a mouth and oesophagus, which has neither stomach nor intestines, because another animal has possessed itself of them for its own use? The study of the lower animals abounds in surprises of this kind. It is a chain of unforeseen facts; of natural impossibilities; of realized points necessarily reversing all notions obtained in the study of beings which have a higher place in the animal scale. The history of the star-fishes would be incomplete were we to omit mentioning the most remarkable traits of their organisation with which naturalists are acquainted. The animals exhibit in the highest degree the vital phenomena of dismemberment and restoration, that is to say, of the faculty of reconstructing organs which they have lost. These arms, the structure of which is so complicated, and which protect such important organs, may be destroyed by accident. The animal troubles itself little at this mutilation: if he loses an arm it disquiets him but little; another is immediately procured. We often see in our collections of Asterias specimens wanting in symmetry because they have been taken before the new members which are in process of development have attained their definite length. Professor Rymer Jones mentions an instance of redintegration very complete and most curious. This naturalist had an isolated ray of Asterias which he had picked up; at the end of five days he observed that four little rays and a mouth had been produced; at the end of a month the old ray was completely destroyed, and this apparently useless fragment had been replaced by a new being, quite perfect, with four little symmetrical branches. This faculty of reproducing organs, which we have noted in describing the fresh water polyps, the sea anemone, &c., exists also in many other zoophytes, but in none more strikingly than in the Asterias. But a still more startling fact remains to be mentioned: one more strange and more mysterious, for it does not belong to the physical or organic order, but appears to belong to the moral world. The star-fishes commit suicide! Certain of these animals appear to escape from dangers which menace them by self-destruction. This power of putting an end to existence we only find on the highest and lowest steps of the animal scale. Man and the star-fishes have a common moral platform, and it is that of self-destruction! This power of dismemberment, however, seems to be confined to the _Ophiocoma_ and _Luidia_--at least, it is only carried out to its full extent in these generæ.