ON THE DEVELOPMENT OF THE SPERMATOZOA. 
83 
suggested the following terminology. The term spermatospore 
(parallel to oospore, denoting the ovarian egg-cell) is applied to 
the constituent cells of a testis, derived from the primitive germ- 
epithelium. These, by division of their nuclei, form spermato- 
spheres or sperm-polyplasts. Each constituent of a sperm- 
polyplast is a spermatoblast, and when the process of division is 
over each spermatoblast becomes a spermatozoon. 
The spermatoblasts, as a rule, stand out like buds from the cell 
which generates them, hence the name sperm-buds (spermato- 
blasts) applied to them. The whole of the spermatospore does not 
appear to be used up in the process of division to form spermato- 
blasts ; a central or eccentrically placed portion, which may or may 
not be nucleated, remains passive, and serves to carry the spermato- 
blasts. This body, which, as will be seen below, has a central 
position in the earth-worm, is to be called the ' sperm blasto- 
phor ^ or ^ blastophoral cell.'’ The terms thus defined find 
their application in a variety of different animals, and it appears 
probable, from my investigations on Lumbricus, Tubifex, 
Hirudo, Helix, Arion, Paludina, Eana, Salamandra, and Mus, 
that the primitive spermatospore always give rise to a passive 
blastophor and peripheral spermatoblasts, which latter only are 
directly converted into spermatozoa. 
The earliest condition of the spermatospores (excluding their 
embryonic phases) is seen in a teazed testis. They are spherical 
corpuscles, averagiug *01 mm. in diameter. The nucleus is com- 
paratively very large and possesses a well-marked nucleolus ; the 
thin coat of enveloping protoplasm is granular, and often of a 
prickly appearance (Plate YI, fig«. 6 — 10). 
In a preparation of a young seminal reservoir the next stages 
of the formation of the spermatozoa will be seen. Many of 
the primitive corpuscles are seen with two nuclei, and an 
intermediate constriction of the enveloping protoplasm, which 
is often very scanty, but distinct when it is marked by 
granules. The thorny processes of the protoplasm may still 
continue (figs. 16 — 20). Next to this in a normal series 
comes the corpuscle with four nuclei (figs. 21, 22), but abnor- 
mal forms with three do occur (figs. 23). Growth of the 
whole cell continues, so that each of the segments in this stage 
may be as big or bigger than the primitive spermatospore ; the 
nucleoli are large and distinct, often situated near the periphery of 
the nuclei. The amount to which the protoplasm is constricted in 
agreement with the nuclei varies slightly ; sometimes the segments 
look as if they were cpiite separate, at other times as if they 
were bound and held together in an investing matrix. 
The spermatosphere or polyplast, which exhibits eight seg- 
ments, is the normal follower of the (quadripartite spheroid (figs. 
