The germ-cells. 641 



many in the pericardial region in situations, similar to those described 

 in the preceding specimen, and there is at least one in the epiblast. 



In the commencement of the abdomen they crop up in numbers 

 in the mesoblast. Just in front of the pronephros there is a big 

 group of them, attached to the outer or coelomic side of the splanchno- 

 pleure, near the point where this passes on to the yolk-sac. There 

 are at least 16 cells in the group, and it is shut otf from the body- 

 cavity by a capsule of flattened peritoneal cells. Rather further back 

 than the front end of the pronephros, and in the region between the 

 first and the second normally placed germ-cells, there is a similar 

 encapsuled group. 



Still further back in the genital region my notes give no details 

 beyond the fact, that there are many wandering germ-cells between 

 the layers. Most of these are connected with the splanchnopleure, 

 being either on or beneath it. The large ones are very abundant in 

 this embryo in front of the actual genital region, while those met 

 with in the abdominal region seem to possess a preference for the 

 splanchnopleure, or its neighbourhood — a point, possibly, of import. 



IV. The Oerin-Cells of Embryos of 6 -8 mm. 



There are several figures from an embryo (No. 393) of 6.5 ram, 

 and this may be referred to as representative of many embryos of 

 6—8 mm examined. The figures are Figs. 23 to 27, 29, and 34 to 36. 



From an extensive table of classification of skate-embryos it may 

 be gathered, that on the average an embryo of 6.5 mm possesses 55 

 to 60 somites and either two or three branchial pouches, the latter 

 number being present with 60 somites. Embryos of 7 to 9 mm possess 

 65 to 88 somites and either three or four branchial pouches. 



In embryo No. 393 the number of normally placed germ-cells is 

 at an extreme estimate 165. This number is the very utmost, and 

 it is probably exaggerated. As to the remaining ones they occupy 

 positions very like those described in the three preceding embryos. 

 Thus, there are notes of their occurrence in the gut-epithelium, in the 

 splanchnopleure, under it, and in many other places. There is one 

 in the gut-cavity. There are two fine large amoeboid ones between 

 splanchnopleure and gut, others appear here and there in like posi- 

 tions. The peculiarity of these two is that they appear to be multi- 

 nucleated. This is again of importance. 



Of the figures from No. 393, Fig. 27 shows two aberrant germ- 

 cells in the pericardial region between epiblast and mesoblast. Tak- 



