4!)G Emanuel Trojan: 



in length, the ;,young embryos" were very, abundant, lying in 

 the coiinective tissue of the inoUiisc. Drawings of a few are 

 giveii lipon plate 3. In the eaiiy stages the cells are grouped 

 regularly enough. The 2, 4 and 8 cell stages ^) may all be easily 

 found in certain individuals. At the 16 and 32 cell stages the 

 ,.young embryos", are l'or the mose part of irregulär contour, 

 ellipsoidal rather than spherical and with a cell or two projecting 

 beyond the others here and there and thus marring the symmetry 

 of the whole. The cells are mostly vacuolated. Further than 

 the 32 cell stages I could not trace the young embryos, but in 

 several stages, they seemed to divide transversely. 



In certain individuals of Phyllirhoe, there may be noticed 

 local aggregations of tiny nuclei which stain well and which I 

 believe may be the spermatozoa of the Mnestra. These nuclear 

 aggregations secured in the connective tissue, in the neighbourhood 

 of and rather posterior to the hermaphrodite glands of the 

 Phyllirhoe, It is supposed that the sperm mother cells of the 

 Mnestra wander to the position indicated and that the process 

 of spermatogenesis occurs there. Fertilisation and the subsequent 

 development would take place within the body of the Phyllirhoe 

 of the embryo." Und an einer anderen Stelle (S. 48) meint er: 

 „The migratory propensities of the germ cells of the Hydrozoa 

 are universally acknowledged: is there any difficulty in imagining 

 that germ cells which have originated in the manubrium of 

 Mnestra are attracted by plentiful nutriment and wander into 

 the nutrient liquids within the Phyllirhoe?" 



Endlich wjU in letzter Zeit VessicheUi (1906j jene 

 Bildungen der Körperoberfläche von Phyllirhoe richtig erkannt 

 haben und beschreibt sie folgender Art: „Questi gruppi cellulari 

 appariscono ad occhio nudo come piccole raacchie biancastre, 

 raccolte costantemente tanto a destra che a sinistra in due 

 distinte zone; Tuna in sopra del cieco postero dorsale, e Faltra 

 in sotto del cieco postero-ventrale (Fig. 1). Ne nella regione 

 codale ne nella metä anteriore del corpo ed ancora meno in 

 prossimita della piede si constata la presenza di un solo di questi 



^) It must be stated tliat in as much as it is not ahvays easy to 

 enumerate the exact number of cells in each enibiyo the numbers 8. 16. 

 32 must be taken as approximate only ; or merely as descriptive terms 

 to imply that the actual number of cells in the enibryo is about that number. " 



