8 GEORGE T. HARGITT 



killed in the midst of an amoeba-like action. The mode of for- 

 mation of the gonophore, however, suggests more of a passive 

 transportation of the egg cells due to the growth of the stem and 

 gonophore; this would be sufficient to account for a part of the 

 translocation of these cells. Goette ('07) has pointed out the 

 probability^ of this as a factor in the location of germ cells within 

 the gonophores of other hydroids, and it seems to be significant 

 here. Figure 6, an optical section of a very young gonophore 

 rudiment, shows the point clearly. The hydranth which be- 

 comes entirely transformed into several gonophores is almost ses- 

 sile as it first arises, but ultimately it has a long stem or pedicel. 

 The growing point is in the stem below the hydranth, and any 

 germ cells which might have been in the young rudiment would 

 be pushed far away from the main stem in the growth of the 

 hydranth stalk. At A in figure 1 and in the hydranth between 

 A and B we have the region of formation of future gonophores. 

 Germ cells are already present here in the stem, and when the 

 tissues of the stem begin to evaginate to form the gonophores, 

 the germ cells present would be carried outward during growth. 

 This would account in part, but probably not entirely, for the 

 presence of germ cells in the gonophores. 



Some indirect evidence also bears on this same question of 

 migration. It is very common to find the conditions shown in 

 figure 4, where a stem contains large and small germ cells side 

 by side. If there be a definite germ region and a definite path 

 of migration, a section of any portion of the stem should con- 

 tain germ cells of about the same size; the presence of large and 

 small egg cells in the same region, therefore, may be taken as 

 evidence of the formation of the small cells in that position. If 

 the evidence is accepted, the large cells may be considered to 

 have arisen in that same location and their shape is not indica- 

 tive of migration. Other evidence is at hand which seems to 

 suggest the formation of egg cells at various places, a growth in 

 those positions and little or no migration. Figure 1 shows 

 groups of cells all along the branches, some large and others 

 small, each group centering about a lateral hydranth or gono- 

 phore. Such a condition is more consistent with the origin of 



