SPERMATOGENESIS OF EUSCHISTUS 783 
is not produced in the spermatocytes or the spermatids. There 
is much need of a careful study of it in the spermatogonia, for 
its genesis is by means fully established. 
A second body is a more or less spherical, lunar or cup-shaped 
structure that encloses the centrioles so long as they remain at 
the distal pole of the nucleus. Meves (1897) has named this the 
‘idiozome,’ and later (’02a, p. 53) the ‘centrotheca.’ Previously 
it had been called variously ‘sphere,’ ‘attraction sphere,’ ‘archo- 
plasm’; but Meves pointed out that since it has no connection 
with spindle fibers, but disintegrates before the metaphase of 
mitosis, it is quite different from the attraction sphere of Van 
Beneden and the archoplasm of Boveri. A new and interesting 
relation in Euschistus is that the idiozome always touches the 
nucleus at that region where the chromatin composes a particu- 
lar peripheral chromatin plate; the only other writers who have 
found a similar chromatin plate are Pantel and de Sinéty (’06), 
but they described it as a thickening of the nuclear membrane 
(their fig. 10). In the spermatogonia this chromatin plate, and 
with it the idiozome, may lie at any pole of the nucleus, though 
both are always together; but in the spermatocytes the idiozome 
is invariably placed against the distal pole of the nucleus, where is 
also invariably the chromatin plate, and in these cells this chro- 
matin plate is composed of the ends of two or three chromosomes. 
Further, when the idiozome disintegrates, the chromatin plate of 
the nucleus also becomes disestablished. This constant local 
connection of these two structures suggests a nuclear influence 
in the formation of the idiozome. So soon as the centrioles 
wander apart from each other and pass out of the idiozome, 
the latter disintegrates; therefore it may be that the centrioles 
also have something to do with the formation of the idiozome, 
an idea treated specially by Buchner (710). In Euschistus no 
idiozome develops in the second spermatocytes or in the sperma- 
tids. 
In oogonia and the earlier stages of oocytes occur bodies quite 
comparable to the idiozomes of sperm cells, agreeing in position 
as well as in containing the centrioles; Van der Stricht (05, ’09) 
