Of course, of the larger ones there is nothing to be found after Professor Gibbes has gone over the ground, but among the lower orders there are a great many in store for a microscopic observer. I have only to regret that I cannot apply myself more steadily. I find my nervous system so over-excited that any continuous exertion makes me feverish. So I go about as much as the weather allows, and gather materials for better times. Several interesting medusae have been already observed; among others, the entire metamorphosis and alternate generation of a new species of my genus tiaropsis. You will be pleased to know that here, as well as at the North, tiaropsis is the medusa of a campanularia. Mr. Clark, one of my assistants, has made very good drawings of all its stages of growth, and of various other hydroid medusae peculiar to this coast. Mr. Stimpson, another very promising young naturalist, who has been connected with me for some time in the same capacity, draws the crustacea and bryozoa, of which there are also a good many new ones here. My son and my old friend Burkhardt are also with me (upon Sullivan's Island), and they look after the larger species, so that I shall probably have greatly increased my information upon the fauna of the Atlantic coast by the time I return to Cambridge. In town, where I go three times a week to deliver lectures at the Medical College (beside a course just now in the evening also before a mixed audience), I have the rest of my family, so that nothing would be wanting to my happiness if my health were only better. . .What a pity that a man cannot work as much as he would like; or at least accomplish what he aims at. But no doubt it is best it should be so; there is no harm in being compelled by natural necessities to limit our ambition,--on the contrary, the better sides of our nature are thus not allowed to go to sleep. However, I cannot but regret that I am unable at this time to trace more extensively subjects for which I should have ample opportunities here, as for instance the anatomy of the echinoderms, and also the embryology of the lower animals in general. . .