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Show 1891.] BATHYBIAL FISH FROM THE BAY OF BENGAL. 227 half a millimetre in the major diameter and a little less in the diameters. The fact of the viviparity of Saccogaster maculata being thus established, we may infer that the genital papilla of the male is an organ for effecting the internal impregnation of the ova. In the female no copulatory modification of the oviduct can be made out; but the circumference of the genital pore is thickened and spongy. In the males of two other Brotuline Ophidiids (namely, Dine-matichthys iluocceteoides and Bythites fuscus) post-anal appendages have been described, and as a converse inquiry we may ask whether these two species may not be viviparous. The inflated condition of the abdomen in Saccogaster maculata is doubtless directly related to the viviparous process; but it is interesting to note that this character is nearly as well marked in the adult male as in the adult female. Again, the peculiar arrangement of the scales, which are scattered and non-imbricating, is probably one of the implications of intra- Saccogaster macidata. abdominal gestation ; for it would facilitate the increasing distension of the abdomen which must follow the growth and enlargement of the embryos. And it is worthy of note that this character also is as conspicuous in the male as it is in the female. The drawing represents the male of Saccogaster macidata, natural size. These notes are, I am well aware, very incomplete. We require to know something of the histological appearances of the ovarian wall-whether or not it is furnished with glands or other structures which might supply nutriment to the developing embryo, through the yolk-sac or otherwise. W e require to know more of the details of structure of the embryo-whether or not it possesses any organs for absorbing nutriment beyond that supplied by the yolk. But the scanty material available is not in a fit state for histological manipulation ; and as the capture of a pregnant female of a particular species of deep-sea fish is not an event to be calculated upon with any certainty, I venture to present these rough notes on an interesting subject just as they are. 15* |
