DL_ANN ALES MUSEI NATIONALIS HUNG ARICI. 19 il 
DEGENERATION AND PHAGOCYTOSIS OF THE EGG-CELLS 
OF THE GASTROPODS. 
By Dr. L. Soós. 
(Plate VII and 1 textfigure.) 
For a long time it has been known that the ovarian eggs of some _ 
animals enlarge themselves by incorporating other cells. Such cases are 
known in the Coelenterates, Tunicates and Molluscs. 
The eggs of the Coelenterates (Hydra, Tubulariidae, Codonidae, 
Cladonemidae) are originally similar to the other cells of the germinal 
tissue. Some of these cells, which are supposed to be in a more favor¬ 
able position, begin to increase at the expense of their brethren 
[Tubularia larynx , Doflein (5)], and gradually transform themselves 
into egg-cells. The egg-cells enlarge themselves further by ingesting 
their neighbouring cells, which are visible in the cytoplasm for a long 
time, and are known under the name pseudocells (Kleinenberg). Thus 
too increase the egg-cells of Hydra [Kleinenberg, Brauer (B)], Tubularia 
larynx [Doflein (5)], Tubularia coronata [Grönberg (9)}, Myriothela 
phrygia (Labbé), Margeleopsis Haeckeli, Steenstrupia galanthus, Hybo- 
codon prolifer [Müller (14)]. The observers agree as regards the process 
itself, but differ in intei preting it. Some authors (Balfour, Metchnikoff, 
Tichomiroff) are of the opinion that the egg-cells devour the nutritive 
cells like Amoeba , the others (Doflein, Müller), however, maintain 
that the egg-cells don’t ingest the cells in question, - but the, cytoplasm 
of the nutritive cells fuse with that of the egg-cells, and only the 
nuclei of the former become digested. 
In a similar way the eggs of the Ascidians increase. They deVe- 
lope in a follicle, some cells of which separate — according to Floderus 
(8) — and form a nearly perfect layer along the inner side of the fol¬ 
licle wall. These are the so called testa cells, which later migrate into 
the interior of the egg-cells, and serve as food for them. 
The eggs of the Pulmonates — according to the literature — 
enlarge by ingesting foreign cells. Balbiani seems to have been -the- 
ffrst to observe foreign cells migrating into the interior of the egg 
cells of Helix which were regarded by him as epithel cells. More detailed 
