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Show •140 MR. P. W. BA.SSETT-SMITH ON [Apr. 18, well demonstrated by Hesse; and the very interesting metamorphosis that the Lerncea branchialis goes through before becoming a fixed inert sac has been beautifully worked out by C. Claus, who has shown that copulation takes place when the animals are of very small size, the maturity of the ovules keeping pace with the increased growth of the female. The young unattached forms of this species have been taken in the tow-net by Mr. I. C. Thompson on more than one occasion ; the juvenile conditions of other genera have been taken free, having been described as Baculus and Hersellia, which are probably the young of Penella. Iu the family Ergasilidae (p. 441), the genus Thersites Pagenst. does not appear to me to be distinct from Ergasilus, the only species of the former having been described from the gills of Gasterosteus aculeatus, from which, too, a species of the latter genus is taken; I have therefore united them together. In the family Caligidae (p. 444), the numbei of described species of Caligus is very large, and some of them have undoubtedly been known by many names ; these I have endeavoured to place in their proper places. The genus Papulina of Van Beneden has been relegated to Lepeophtheirus, from which it has no marked differences ; his genus Oalina has been established, but the specimen described by him as Galigeria belongs to the old-formed genus Alebion of Kroyer. The Lepeophtheirus huttoni of Thomson, taken in N e w Zealand, a specimen of which he has been good enough to send me, should be placed with Gloiopotes Stp. & Liitk. Examples of the same species are present (unnamed) in the British Museum, taken at Madras. The genus Nogagus has been entirely left out, as it contains only male forms of other genera. The name Peris-sopus has been retained for Dana's Lepidopus, which is already in use, and Van Beneden's Ghlamys is of more recent origin. In the family Dichelestiidae (p. 468), the genus Epachthes has been kept for a single species described by Nordmann, though the generic differences of this from Lernanihropus are very doubtful. Two new genera described by m e in 1898 (Cybicola and Pseudo-clavella) have been added. The family Philichthyicbe (p. 477) has been formed to include all those parasites which are found only in the mucous canals and sinuses of various fish, and are so constructed as to be able to move freely in these spaces, the female having neither articulate limbs nor strong organs of attachment; the male is, however, of a distinct and rather high crustacean type. The first form found was the Philichthys xiphce, Stp.; it was placed in the last-mentioned family, though the female resembled much a Chonclracanthus. Hesse was the first to discover the minute forms, which he divided into two genera, Lepiosphile and Colobomatus. Since then Bichiardi has described eight species of Philichthys, but they differ so much from the original that I have made for them a new genus, giving to it his name. Hesse, Bichiardi, and Carl Vogt were strongly of opinion that these peculiar animals were worthy of being formed into a family of their own, especially as the known males are much alike aud distinct. |