166 Miscellaneous. against the walls of the cell, the larva travels towards the opercultim in the same way that an ear of rye, by the aid of its spiny beards, can travel over a piece of cloth which is set in vibration." The comparison employed by M. de Saussure is quite correct ; but the spines are not, properly speaking, ujDon 4he abdomen ; they are situated on the cerci, which have the form of two large mamillse. Moreover the legs are covered Avith strong spines, which likewise assist the young larvae to travel in their alveolus. The larvae of the upper part of the case are the first to issue, although these eggs were the last laid. Sometimes the lid of the cc41 closes again before the larva has completely issued and it perishes. Those which succeed in quitting the ootheca, instead of falling to the grouud, are sustained in the air by the aid of two very long and very slender silky threads, fixed on the one hand to the extremity of each of the cerci, and on the other adherent to the inner and posterior wall of the shell of the egg. Very soon all the little larvae thus suspended from the ootheca form a sort of bunch. They remain for some days in this state ; and when the first moult has taken place, their cast skins remain suspended from the ootheca. If these young larvte were to fall to the ground in such a feeble state, they would become the prey of their enemies. After the moult they manifest their voracity by falling upon the small insects they meet with, and they are very active. The silky threads which sustain these young larvae have been regarded as the representatives of the cerci ; but in the larvae con-tained within the egg the cerci already exist, and are formed, as I have already indicated, by two short rods covered with spines. It often happens that, in order to change the skin, the larvae of these insects are obliged to attach themselves to the branches by means of filaments. These long silky threads seem to have no other purpose but to enable the larva to effect its first moult secure from all dangers. — Gomj)tes Rendus, July 11, 1881, p. 94. Observations on Cladocoryne floccosa. By M. DuPLEssis. M. Duplessis's memoir on Cladocoryne floccosa (Bull. Soc. Vaud. des Sci. Nat. 2^ ser. tome xni. pp. 108-118) furnishes us with complete information upon a curious type of Hydroids which is the solo representative of a distinct family. The distribution of the tentacles, their dichotomous branching, and their knobbed termina-tions would seem to bring Cladocoryne into the family Cladonemidae or into that of the Clavatellidae. But in both thcce families the polypes produce Medusae, while the genus Cladocoryne is larvipa-rous. It approaches the family Corynidae by the constitution of its genital capsules and by the arrangement and form of its tentacles ; but it is the only larviparous genus in which the latter organs are branched. Unless we were to modify the diagnosis of the Corynidae we must therefore form a family Cladocorynidse, including the
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