208 BUNTING. [Vor Lx 
Fig. 45, although there may be some exceptions to this rule in 
the position of the ova. The sex-cells reach maturity in 
gonophores, the larger and more advanced of which appear in 
the lower part of the germinal zone, while there is a gradual 
decrease in size, and age, as these pass towards the upper 
portion, shown for the blastostyle of both sexes, Pl. II, Fig. 47, 
female, Fig. 46, male. 
The ova are found to be quite abundant in the endoderm 
of the blastostyle, even before there is apparently any trace 
of the gonophore. I have failed to observe in all cases that 
the older ova are found in the lower part of the germinal 
zone, the younger ones towards the upper part, as Weis- 
mann states. And I have found that they do not always 
rest upon ‘the “Stiitzlamelle,” thus “‘Man sieht hier, wie 
die Eizellen nach oben hin rasch an Grédsse abnehmen, wie 
sie alle unmittelbar auf der Stiitzlamelle aufliegen, und wie 
die Bildung neuer Eizellen durch kleine Keimzellen vorbereitet 
wird, welche durch Theilung sich vermehren und alle ebenfalls 
auf der Stiitzlamelle fussen” (p. 77). I should conclude as a 
result of my studies that the ova, while frequently found in 
the position recorded by Weismann, are not unusually seen 
at the oral pole; even at ‘the tentacles, “as: shown “by PL i, 
Fig. 2; the younger ones in the lower part of the germinal 
zone, the older above as in Pl. I, Fig. 1; again I have not 
always found them upon the “ Stiitzlamelle,” as this figure also 
illustrates. 
I have endeavored by close study to trace, if possible, these 
sex-cells to the ectoderm of the blastostyle, since Weismann 
assumes this to be most likely their true place of origin; but 
have failed to find the slightest evidence of their appearance 
in this layer, other than that the ectoderm in this portion of 
the blastostyle is closely crowded with nuclei, and becomes 
thicker in this region. Since the ova may appear at such 
different places in the endoderm, it seems rather safe to assume 
that the germ-plasm for the formation of the ova is present in 
the endoderm, and that while this germ-plasm has inherited a 
tendency to develop ova in a definite region, yet that under 
certain conditions ova may develop from it in other regions, 
