496 Miscellaneous, I placed my captive in a glass vase, and his having selected the side of the glass for burrowing (probably from the glass forming one firm side to the work), enabled me to watch every movement ; the sand appeared to be passed to the mouth of the hole by the legs and false legs, when it filled round the body and filled in as the animal passed downwards. The antennae are delicately sensitive. I believe this sensitiveness depends on the sense of touch : the slightest contact with them sets the animal in motion (and this when it is buried some depth), using every exertion to burrow deeper. It is evidently a night-feeding genus, as it remained buried and inactive during the day, but the state of the sand in the tank in the morning proved that it had not been idle during the night. From these facts I am justified in stating that Nika edulis is a burrowing species (if not of a burrowing genus), and that its bur-rowing is only by day to hide itself from its enemies, and not to procure food. The description I have given of the colouring of this species will be found to be different from that given by Risso, as stated by Mr. Milne-Edwards. I should have great diffidence in differing from these eminent naturalists had I not imagined that their descriptions might have been taken from cabinet specimens. Had I waited to describe my specimen until after its death, I must have described it as it now is, namely, Jlesh-red ; I find all the thinner-shelled Crus-tacea change more or less of a flesh-red, with the exception of the CrangonidcB. — Proc. Zool. Soc, April 22, 1856. NAUCRATES DUCTOR. To the Editors of the Annals of Natural History, Falmouth, November 1, 1856. Gentlemen, — A shoal of the Naucrates ductor, Cuv., made its appearance in shallow water. Custom House Pier, on Friday afternoon, Oct. 31, 1856, and more than three dozen of them were caught in nets, baskets, &c., by persons on the beach. I have procured species of this interesting fish every year during my residence in this neigh-bourhood. I am, Gentlemen, yours truly, W. P. Cocks. On Peculiar and Quasi-spontaneous Movements of the Plasmatic Cells of certain Animals. By Prof. Kolliker. I have just observed at Nice, upon a fine animal of the family of the compound Ascidians, which according to M. Milne-Edwards has not yet been described, a very peculiar fact, namely, movements of the cells which occur in great number in the gelatinous substance common to the whole bunch and formed of cellulose. These cells, which are round or stellate and of very various forms, have, in the living animal, a slow, but easily perceptible movement, consisting in a constant change of form, so that the same cell, which was at one time round, becomes stellate or fusiform in different degrees, by the
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