being filled with the small brightly staining spermatocytes. Ova and spermatozoa when mature are set free in the stomach pockets. 10. _Floating and Wandering Cells._ In the stomach pockets, the canals of the sensory clubs, and even in the stomach itself, are found in varying numbers freely floating cells having the appearance of young ova. They vary in size, the smallest being of the size and having the general aspect of the small ovocytes found in the ovary. The largest (Fig. 70) have exactly the same structure as the young ovarian eggs before they have begun to accumulate yolk. The granular deeply staining cytoplasm, the clear non-staining nucleus with its bright nucleolus and the nucleolus-like yolk nucleus, all show beyond doubt that these freely floating cells originate in the ovary. In some of my preparations these cells are found not only floating free, but wandering through the tissues. Fig. 70 shows two such wandering cells fixed just as they were making their way either through the digestive epithelium into the gelatine of the floor of the stomach, or from the gelatine into the epithelium. The former seems the more probable, though why they should want to get into the gelatine is not very easy to conceive. Perhaps there is some connection between this and the appearance that the young ovarian eggs have of pushing their way from the epithelium into the gelatine of the ovary. And of course it is not impossible that the whole phenomenon is abnormal, due to rupture of the ovaries which sets free young ova to exhibit their amœboid tendencies under new conditions. Against such an explanation, on the other hand, might be urged the fact that what seem to be the small floating cells are found occasionally in males as well as females, and that in the females a series can be traced with a good degree of certainty between the small floating cells like those found in the walls, and the larger ones which have all the characteristics of young ova. However that may be, this amœboid action of cells having the structure of ova brings to mind the remarkable form of asexual reproduction described by Metschnikoff for Cunina proboscidea, under the name of “Sporogonie.” Unfortunately Metschnikoff’s original paper was not accessible to me, so that I was unable to obtain more particulars on the subject than those given in Korschelt and Heider’s text-book (p. 33). The reproductive organs of both males and females of Cunina proboscidea are said to produce, besides the usual distinctively sexual elements, neutral amœboid germ cells, which wander into the endoderm of the stomach and circular canal, and also penetrate into the gelatine of the subumbrella. These amœboid cells divide parthenogenetically. One of the two cells of the first cleavage continues to divide and eventually forms an embryo of Cunina; the other remains amœboid and serves for movement, attachment and nourishment of the embryo.