70 Proceedings of the Royal Society of Victoria. 



The ovum, of which I have found one example in my 

 sections, ap])eai-s in section as a somewhat oval cell, lyii'g in 

 a fibrous capsule, as described above. The body of the ovum 

 is granular and deeply staining. At one pole there is a laige, 

 oval nucleus, with a very definite wall, and right up against 

 the wall at the outer pole of the nucleus there lies a small, 

 spheiical nucleolus. Within the nucleus there is a quantity 

 of coarsely granular protoplasm, chiefly aggregated towards 

 the jjole remote from the nucleolus. The nucleolus stains 

 deeply and is ahnost if not quite homogeneous. 



The embryos, which are abundant, are spherical solid 

 bodies, about as large as small peas. When the surface of 

 the embryo is examined with a pocket lens, it exhibits a 

 minutely punctate appearance, due to the presence of an 

 immense nuujber of shallow pits, somewhat polygonal in 

 outline and separated from one another by low ridges. 

 Eacli one of these pits is the i)n{)rint of one of the large 

 epithelial cells of the embryo capsule. 



In sections, the embryo is seen to consist of an outer layer 

 of rather large, closely packed cells, enclosing a central mass 

 of clear, transpaient, jelly-like substance, in which immense 

 numbers of amoeboid wandering cells are imbedded. The 

 outer layer, or ectoderm, consists of a. single layer of large, 

 sac-shaped or somewhat flask-shaped cells, measuring about 

 0024- mm. in length. The narrower portion, or neck of the 

 cell is on the outside of the embryo, and the swollen portion 

 l^rojects inwards into the gelatinous intercellular substance, 

 and from its inner extremity the ceil frequently .sends out a 

 few short, slender, protoplasmic processes, resembling 

 pseudopodia. The body of the cell is coarsely granular, but 

 less so in the neck than in the swollen portion. Ihe greater 

 part of the neck is, ho we vei-, occupied by a large, spherical 

 nucleus, which appears to consist of a hollow vesicle 

 containing a few deeply staining granules. The nuclei of 

 adjacent cells ai-e all an-anged ;.t just about the same level, 

 so that they form a continuous row, which is a very 

 conspicuous feature in transverse sections of the embryo. 



Frequently the outer end of the neck of each ectodermal 

 cell may be seen to be drawn out into a short, slender 

 protoplasmic process, which extends to the outer siu'face of 

 one of the large, investing epithelial cells and attaches itself 

 to it. Thus the ectodermal cells of the e ubryo often appear 

 to lie suspended from the outer surf tees of the investing 

 epitiielial cells b}^ short protoplasmic processes. Judging 



