Towards the end of the month I passed the Vale of Heath Pond, Hampstead, and although I had not gone out for the purpose of collecting, was fortunately provided with a two-dram bottle. Close by the path the _Anacharis alsinastrum_ grew in profusion, quantities of water-snails crawled among its branches, and small fish darted in and out, threading their mazes with lightning rapidity. Thrusting a walking-stick among the mass of vegetation, a few little tufts were drawn up and carefully bottled, with the addition of a little water. Returning home, a few leaves were placed in the live-box, and on examination with the power of sixty diameters they disclosed a specimen of, perhaps, the most beautiful of all the rotifers, the _Stephanoceros Eichornii_. In this elegant creature an oval body, somewhat expanded at the top, is supported upon a tapering stalk, and stands in a gelatinous bottle, composed of irregular rings superimposed one upon the other, as if thrown off by successive efforts, the upper ones being inverted and attached to the body of the animal. But that which constitutes the glory of this little being is the crown of five tapering tentacles, each having two rows of long cilia arranged on opposing sides, but not in the same plane. The ordinary position of the tentacles is that of a graceful elliptical curve, first swelling outwards, then bending inwards, until their points closely approximate, but each is capable of independent motion, and they are seldom quiet for many minutes at a time. The cilia can be arranged in parallel rows or in tufts at the will of the creature, and their motion appears under control, and susceptible of greater modification than is exhibited by the ordinary infusoria. [Illustration: Stephanoceros Eichornii.] The Stephanoceros is a member of the Floscule family, but in all the specimens I obtained and watched for several weeks, there was an important difference in the relation of the tube to the creature. In the Floscules I had never seen anything like an adhesion between the tube and the animal, but in the Stephanoceros I noticed it continually, and always in the manner already described. Like the Floscule, the Stephanoceros is readily alarmed, and retreats into her house, carrying with her the invaginated portion. In the last edition of 'Pritchard's Infusoria,' this case is spoken of as apparently not tubular, but a solid gelatinous mass, enveloping the animal as high up as the base of the rotatory arms. It is very likely that specimens at different ages, and possibly in different seasons, may vary in the structure of their abodes; but I am not able to concur in the preceding account, as all the tubes I examined resembled sacks turned in at the mouths, and attached to the shoulders only of their inmates; and on one occasion I was able to look down into a deserted tube, which had not collapsed, as it would have done if it had been merely a solid gelatinous mass.