To return from this digression to our little Hampstead ponds, we obtained from one, in September, that was full of star-weed, a number of sugar-loaf bodies, adhering to one another, and of a pale yellow brown colour. The specimens first examined looked complete in themselves, and were taken for eggs of some water creature. Further search, however, disclosed aggregations of similar sugar-loaves that had evidently formed part of a tubular structure, and the idea at once occurred that they were fragments of a Melicerta tube, a conclusion that was verified by finding some tubes entire and a dead Melicerta in the rubbish at the bottom. All the specimens of Melicerta tubes we had hitherto examined were composed of _rounded_ pellets, but these were made of pointed cones or sugar-loaves, with the points projecting outwards from the general surface. In Pritchard's 'Infusoria,' these pellets are described "as small lenticular bodies." The 'Micrographic Dictionary' states that the tubes of the Melicerta are composed of "numerous rounded or discoidal bodies;" and Mr. Gosse, in his 'Tenby,' which contains an admirable description, and an exquisite drawing of this interesting rotifer, calls the pellets "round." [Illustration: Melicerta ringens.] Not being able to obtain a living specimen of the Melicerta, who made her tube of long sugar-loaves, I could not tell whether she differed in structure from the usual pattern of her race, but the general appearance of the dead body was the same. It is possible that these creatures possess some power of modifying the form of their singular bricks, or they may at different ages vary the patterns, which matters some fortunate possessor of a colony of these animals may be able to verify. [Illustration: Scaridium longicaudum.] In the sediment of the water containing the Melicerta cases was found an animalcule about 1--120" long, covered with cilia, and having a proboscis seldom more than a quarter of the length assumed by the body, which continually changed its form, sometimes elongating, sometimes shortening, and often contracting one side into a deep fissure. It was, probably, an _Amphileptus_, though not precisely agreeing with any drawing or description I am acquainted with. Another inmate of the same water was a lively long-tailed rotifer, with a small oval body, a tuft of vibrating cilia and a curved bristle visible among them on one side. This creature had a jointed tail-foot, ending in two long style-shaped toes, and by means of this appendage executed rapid leaps or springs. It was the _Scaridium longicaudum_, and agreed in dimensions tolerably well with the size given in the books, namely, total length 1--72". With a power of five hundred diameters the muscles of the tail-foot presented a beautifully striated appearance.