. The physiology of reproduction. Reproduction. 408 THE PHYSIOLOGY OF REPRODUCTION. foetal vessels are related to the orifices of the glands, and appear to be concerned principally with the absorption of their secre- tion. As already mentioned, the viUi may also be concerned with the excretion of waste products of haemoglobin. Bonnet was the first to show that the trophoblast in Ruminants was actively phagocytic and absorbed the consti- tuents of the uterine milk (Fig. 94). He demonstrated the presence of fat-globules, hsemoglobin and its derivatives, de- generated leucocytes and " Stabch
. The physiology of reproduction. Reproduction. 408 THE PHYSIOLOGY OF REPRODUCTION. foetal vessels are related to the orifices of the glands, and appear to be concerned principally with the absorption of their secre- tion. As already mentioned, the viUi may also be concerned with the excretion of waste products of haemoglobin. Bonnet was the first to show that the trophoblast in Ruminants was actively phagocytic and absorbed the consti- tuents of the uterine milk (Fig. 94). He demonstrated the presence of fat-globules, hsemoglobin and its derivatives, de- generated leucocytes and " Stabchen " (Fig. 95)—in short, aU the histologi- caUy demonstrable constituents of the embryotrophe — in the trophoblast. Many, if not all, of the cellular ele- ments are partially degenerated before absorption. The appearances suggest an enzyme action on the part of the trophoblast, and perhaps also the leucocytes, but no proteolytic or lipolytic enzyme is contained in glycerin extracts of the maternal or foetal part of the cotyledon. After their absorption, the disin- tegration of the cellular constituents is completed in the trophoblast, and they are no longer recognisable as individual elements. Their products are transmitted to the foetal vessels, though they may first be elaborated in the trophoblast into a form or forms suitable for the use of the embryo in the development of its various organs. Lemuroidea.—Many of the lemurs have a simple aviUous diffuse placenta, as Turner ^ first pointed out in specimens from Madagascar. Hubrecht has investigated two others found in the East Indies—Tarsius ^ and Nycticebus.^ The latter has also a diffuse placenta. Vilh develop over the whole of the ^ Turner, " On the Placentatlon of the Lemurs," Phil. Trans. Boy. Soc, London, vol. clxvi., 1876. ^ Hubrecht, "Ueber die Entwickluug des Placenta von Tarsius," & Internal. Congr. of Zool., Cambridge, 1898. ^ Hubrecht, " Spolia Nemoris," Qvxir. Jou
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