808 
Proceedings of the Royal Society 
exhibits an endogenous formation of nuclei, which, travelling 
outwards, form the spermatocyte-cells, apparently budded out on the 
surface. The mother-cell degenerates, the nucleus alone remaining 
to serve as a basis of attachment for the spermatocytes, but finally 
also undergoing atrophy. With this, Keferstein’s account in general 
agreed. M. v. Brunn, however, denied the endogenous formation 
of nuclei, and maintained the persistence of the basal-cell to form 
new generations of spermatocytes. Blomfield also described in 
Helix the division of the spermatogonia to form morula-masses 
(“spermatospheres”) of “spermatoblasts,” one of which (the “blasto- 
phoral cell,” situated next the ampulla-wall) is, at an early stage, 
marked off from the others, remaining inactive while the other 
“spermatoblasts” of the “polyplast” are more or less supported by 
it, in their continued multiplication. What Duval had described in 
the snail, Hallez corroborated by the observation of an essentially 
similar process in some Planarians ; while Graff found in other 
species that no cytophoral remnant survived, but that the whole of 
the spermatogonium became converted into a “ sperm ato-morula ” 
of spermatocytes. The spermatogenesis of some Trematodes was 
described by Lorenz (1878) as consisting in the enlargement of an 
epithelial cell, the endogenous appearance of nuclei, and segmenta- 
tion into a morula-like mass of somewhat indistinctly separate cells, 
round a small central remnant. In 1880 Blomfield investigated 
the process in the earth-worm, and described how a “ spermatospore” 
cell divides into a number of “spermatoblasts,” with a central mass 
of inactive protoplasm, the “ blastophore,” — the whole result forming 
a “ spermatosphere,” of which each of the “spermatoblasts” is 
differentiated to form a spermatozoon. His results are, on the whole, 
more analogous to those of Yon Ebner than to those of La Yalette. 
Besides his subsequent research on the spermatogenesis of the snail 
to which we have already alluded, he described that of the frog. 
In this case a hollow spermatogemma arises, each of its cells 
elongates to form a spermatozoon ; these, while immature, arrange 
themselves in bundles round one of the more superficial cells, which 
“become blastophoral corpuscles,” — a view which recalls Merkel’s 
explanation of Yon Ebner’s spermatoblasts, mentioned above, viz., 
that the spermatozoa, after completing their development, are only 
temporarily lodged in the recesses of the former. 
