460 Ferguson . — The Development of the Egg and 
gations. There can be no doubt that there is an intimate 
relation between the sheath-cells of the pines and the substance 
of the egg, such as is believed to exist between the follicle- 
cells and the egg in animals. But the exact nature of this 
connexion, in Pinus , is not easily determined. I have rarely 
examined a preparation showing archegonia without studying 
the relation of the sheath-cells to the oosphere ; and yet no 
entirely satisfactory evidence, because not demonstrable 
beyond question, of the origin and nature of the so-called 
proteid vacuoles has been found. 
Hirase (’95) observed that the granules in the egg of Ginkgo 
were of nucleolar origin, being derived both from the nucleus 
of the central cell and from the nuclei of the sheath-cells. 
Arnoldi (’00) found that substantially the same thing was 
true in Cephalotaxus. He was not able to detect the passage 
of the nucleoli from the sheath-cells into the egg, but, since 
these granules were present on both sides of the membrane of 
the egg-cell, he accepted the fact of their transference. I have 
frequently seen a nucleolus partly without and partly within 
the nucleus of a sheath-cell ; but in no instance could one 
be sure that such a condition was not the result of mechanical 
displacement. 
Ikeno (’98) found direct evidence that the nutritive spheres 
in Cycas are of nuclear origin. But no such phenomenon 
as he observed in Cycas occurs in Pinus. Platner (’86) 
described the passage of the follicle-cells into the ovum in 
Helix , and a few other such instances have been recorded 
in animals. Arnoldi (’00) has recently noted a most remark- 
able migration of whole nuclei from the sheath-cells into the 
egg in several species of pines. He has observed, in a single 
series, as many as one hundred and fifty nuclei passing into 
the ovum. From the fact that Arnoldi writes Strobus in 
a parenthesis after Pinus Pence , I infer that he employs 
the terms as synonyms ; but I find no authority for such 
a usage, and cannot accept his conclusions as holding good 
for Pinus Strobus. It does not seem possible that, in a care- 
ful examination of several thousand archegonia, so obvious 
