i88 7 .] 
A Protandric Hermaphrodie. 
15 
In the specimens of Myxine which had well-developed ovarian 
eggs, there was, according to CUNNINGHAM, no testicular portion 
present in the sexual organ. He says: »the only conclusion I can 
draw is*- that in the young state the female are nearly, but not 
• quite always hermaphrodite, and that the testicular portion normally 
disappears as the eggs become more mature«. 
The minute structure of the ovary and the ovarian 
eggs has been the subject of special attention in CuNNlNGHAMs 
researches. We will gi ve a short summary of his results. The ovary 
is extremely thin from side to side; there is no distinct boundary 
between ovary and mesovarium. The mesovarium is attached, not to 
the back of the body cavity but along the line of attachment 
of the mesentery with the straight intestine. The eggs are pro- 
duced at the free edge of the ovary, which is covered by a thin 
epithelium, and the eggs are produced from this germinal epi- 
thelium in the same way as in other Vertebrates, and are sur- 
rounded, after their separation, by a follicle consisting of a connec- 
tive-tissue capsule and follicular epithelium. As the eggs grow 
larger by the accumulation of yolk, they pass inwards towards the 
: attached border of the ovarium, the largest and oldest being always 
the innermost. The connective-tissue membrane surrounding the 
ovum is thick, composed of very thin interlaced flbrils with numerous 
small nuclei, and contains blood-vessels. The folicular epithe- 
lium within this capsule is composed of »several layers« of elongated 
cells, disposed with their axes perpendicular to the surface of the 
epithelium. Within this epithelium is the »vitelline membran e.« 
This membrane is not yet present in quite young stages of the eggs, 
and it is, in Cunningham's opinion, formed by the folicular epithelium, 
which is also present in the young stages of the eggs but only slightly 
developed. The viteliine membrane consists of a single layer only, 
and is in immediate contact with the substance of the ovum proper, 
the vitellus. The polar portion of the vitellus, at a certain pole of 
the ovum, is protoplasmic in its nature, contains the germinal vesicle 
and forms, thus, the germinal disc, whiist the rest of the vitellus 
is filled with yolk-discs. 
The viteliine membrane at one pole of the ovum, that at which 
the germinal disc is situated, is perforated by a micropyle, which 
is produced by the growth of a cellular process from the follicular 
epithelium towards the vitellus, while the viteliine membrane is being 
formed. CUNNINGHAM compares the viteliine membrane in the ovum 
• of Myxine (which possesses minute pores perpendicular to its surface, 
