The germ-cella. 639 



their name is legion. Comparison of this cells (Fig. 24) with the 

 normally placed germ-cells of Plate 43 shows complete agreement. 

 The general question of the germ-nature of this and of other and 

 larger cells will be discussed in a subsequent section, and the powers 

 of amoeboid movement, possessed by germ-cells, will be referred to. 



Thus, then, some of the missing germ-cells of the mesentery are 

 accounted for. Others of them are doubtless represented by such 

 cells as those in a like position depicted in Figs. 29 and 36. These 

 differ from that of Fig. 24 in size. The difference, however, is brid- 

 ged over by such instances as those shown in Fig. 26. These cells 

 again lie between hypoblast and splanchnopleure. The 4 cells of 

 Fig. 26 have obviously arisen by 2 or 3 divisions of one such cell as 

 that shown in Fig. 29, or in Fig. 36 1). The result has been four 

 germ- cells of about the normal size (0.02 mm). 



Wandering germ-cells are very often of larger size than this. 



In addition to these subperitoneal germ-cells there are also others 

 in embryo No. 410 within the gut-epithelium. Cases of this kind 

 occur in all embryos up to those of 20 mm or so. Two such are 

 shown in Figs. 30 and 31. Sometimes, as shown in the figures, they 

 are of the average size of normal germ-cells, at others they exceed 

 this, and resemble those of Figs. 29 and 36 2). 



The aberrant germ-cells of the hypoblast and the sub-splanchno- 

 pleural ones also occur in this embryo and in all other young embryos 

 in front of the future genital region. Nay, they extend far forwards 

 — through the pericardial region, where they are often abundant, as 

 in R. hatis Nos. 402 and 634 (Fig. 8), and into the gill-region '^). But 

 with one trifling and easily explicable exception — to be commented 

 upon later on — they have not been found in the caudal region. 



In Fig. 13 a rarer seat of aberrant germ-cells is depicted from 

 embryo No. 410. The germ-cell of this figure lies in the ventral 

 epiblast of the posterior branchial region. Assuming that all these 

 cells are germinal — a question for subsequent discussion — the mere 

 record of the places of their occurrence must be becoming somewhat 

 monotonous to the reader. It would be a matter of ease to spin out 



1) The cell of Fig. 36 = 16 primary germ-cells of 0.02 mm. 



2) Until the embryo is upwards of 40 mm in length, the average 

 diameter of the germ- cells is 0.02 mm. More rarely such cells possess 

 in the resting phase a diameter of 0.036 mm (Fig. 8). 



3) Compare Eigenmann's finds ('92 and '96) to be referred to sub- 

 sequently. 



