of Edinburgh, Session 1885 - 86 . 
813 
segmentation and subsequent evolution. In Mammals tlie true 
male ovules are small parietal cells, regarded by La Yalette as 
follicular. Eacb divides into a temporarily inert portion (follicular 
cells of La Yalette, germinative cells of Sertoli) and “an active 
male ovule,” which multiplies by division to form a spermatogemma 
of spermatocytes. When the spermatocytes have developed into 
nematoblasts, neighbouring “ supporting cells ” (cellules de soutien) 
behave like the basilar cells of Selachians, and fuse with the inter- 
cellular substance connecting the former, thus producing the sper- 
matoblasts of Yon Ebner. The follicular or supporting cells also 
surround inferiorly the temporarily inert male ovules. 
The research of Biondi, which has just been published, claims to 
have effected a reconciliation of preceding discordant observations 
by attributing the discrepancies to the different stages at which the 
development has been observed. In his observations, which apply 
mainly to mammals, he recognises only one kind of round cell, 
alike in mature and in immature tubules. The epithelial cells of 
Sertoli, the Stutzzellen of Merkel and Henle, the spermatoblasts of 
Yon Ebner, are secondary modifications arising from the proto- 
plasmic debris of the round sperm-producing cells. From each 
primitive-cell (Stammzelle) a generation of cells arise, arranged in 
column fashion, in which one can distinguish three zones — the 
single primitive-cell at the base, two to three mother-cells in a 
second row, and four to six daughter-cells in an innermost third 
row. When the pillar is complete, sperm-formation begins from 
the centre outwards, each nucleus becomes a sperm, the pillar 
becomes a sperm-bundle, and the spermatozoa are squeezed out by 
the pressure of adjacent pillars, while from the primitive-cell of one 
of these a new primitive-cell arises by tangential division, to begin 
anew the formation of a fresh pillar in place of that which has been 
modified. The spermatozoa lying embedded in the debris of unused 
protoplasm and of nuclear remnants, are compacted by pressure of 
adjacent pillars to form a so-called spermatoblast. He refers Sertoli’s 
Keimzelle to the canal wall, and identifies his seminal cells and nema- 
toblasts with his own mother and daughter cells respectively. La 
Yalette’s spermatogonium, spermatocytes, and cells of the sperma- 
togemmae, are equivalent to Biondi’s three stages — stammzellen, 
mother-cells, daughter-cells. In a similarly bold way he briugs the 
