SPERMIOGENESIS OF HELIX ARBUSTORUM. 
331 
PL XL, Figs. 45.). Their nucleus is first ovoidal the longer axis being 
at right angles to the axis of the spindle (Pl. X., Fig. 9.). We find 
in the spermatid, besides the nucleus, the following parts : 1. Two cen¬ 
trales ; 2. the nebenkern ; 3. the chromatoid body; 4. mitochondria 
granules and bodies. 
The nebenkern consists of typical pseudochromosomes (PL XL, 
Fig. 5.), and its constitution agrees with that of the nebenkern of the 
spermatocytes. 
The chromatoid body is, as in the spermatocytes, a considerably 
large mass which is surrounded by a clear area, and becomes stained 
like the chromatin (cf. PL XL, Fig. 14.). 
The two centrioles of the spermatids take their origin from the 
division of the centriole of the second maturation spindle. One of these 
centrioles passes toward the cell membrane, and at last takes up a 
position beneath it (distale centriole, PL X., Fig. 8.). The other cen¬ 
triole, however, passes toward the nucleus, and it takes place immediately 
after the reconstitution of the nucleus in a cup-like hollow of it which 
is turned toward the pole of the disappeared spindle (proximale centriole, 
PL X., Fig. 8.). This centriole is surrounded by the refringent c entro - 
shpere which was described by Bolles Lee under the name byaloplast 
(PL X., Fig. 8.). 
According to researches made upon the spermiogenesis of Helix 
the original position of the centrioles is not that stated above. Accor¬ 
ding to von Korff (55) and Prowazek (98) the 2 or 3 centrioles of the 
young spermatids of H. p ornatici lie close together beneath the cell 
membrane, one of them being near the cell membrane, the other nearer 
the nucleus (distale and proximale centriole). Bolles Lee (12) and 
Godlewski (30, 31) state that the spermatids of H. pomatia have only 
one centriole which lies, according to the former author, near the cell 
membrane, according to the latter author, however, near the nucleus. 
Bolles Lee is of the opinion that the 2. and 3. centrioles mentioned 
by von Korff are identical with the swollen ends of the spindle fibres 
and that the original number of these bodies was equal to that of the 
fibres. According to Nusbaum (87) the spermatids of H. lutescens — a 
species closely allied to H. pomatia — have two centrioles connected 
by centrodesmosis. 
Which of these statements is correct, I have not had the oppor¬ 
tunity of deciding. The centrioles of H. arbustorum certainly occupy 
their definitive position already at the beginning of the development of 
the spermatozoon. 
,The next stage is to be seen on Fig. L, PL XL whfch shows a 
