228 The Significance of Sex. [Jan. 
xii. and xxiii—The multiplication of the nucleus of the spermatogonium when the 
division of the cytoplasm is partially or wholly suppressed, cause$ several spermatids 
(and hence spermatozoa) to be united to or in a single cell, and so forming sperma- 
‘togemmes. a-d illustrate this point, which with: Tee is not the 
concentration of chromatin in one side of the nucleus near a head-corpuscle, the 
formation of a cap in connection ns this kapai is illustrated in g-#. The 
other anew is either the paranucleus or tail-corpuscle. In & the membrane cover-. 
ing the middle and hinder part of the head is lost or not separated away like the cap. 
Thes collar” about the neck is the membrane of the old cell. 
Fic. 73, a-f. Sperm. of Xaédé7¢—Brunn, A. m. A., xii.—a, after Platner, A. m. A., 
xxv., shows the pig the cap and badae m chromatic head envel- 
oping the forward end of the neck-piece or its axis. s the nucleus in two 
parts, the posterior aeae grows smaller, the comin is Danai 3 in the 
anterior part of the anterior portion, which forms the head. e is from Schweigger- 
Seidel, A. m. A.,i., to show the finished SERR 
Fic. 74. Sperm. of Mouse—Brunn, A. m, A., xxiii.—Corpuscles arrange them- 
selves about the axis of the middle piece and build it up, so that in the finished 
specimen the neck is annulated. 
Fic. 75, a—c. Sperm. of Sparrow—Brunn, A. m. A., xxiiii.—Here the cytoplasm 
spins a filament that inde spirally about ihe: axis, but remains separate from it. 
er, <5 Wil. 
. 77. Sperm. of 7riton—Schweigger-Seidel, A. m. A., ii—The sinuous fila- 
ment represents the thickened edge of a delicate membrane, which slings it to the 
tail like a mesentery. See Gibbes, Q. J. M. S., xix., for same structure in salaman- 
der, and Fig. 78, c—e, for the frog. 
Fic. 78, a—-e. Sperm. of Bomébinator—Valette St. George, A. m. A., xxv.—¢ is the 
skeleton left after macerating away the sarc 
, Fic. 79, a-e. Sperm, of Raja clavata—Jensen, A. B., iv. 
PLATE IV. 
Fic. 80, a—e. Sperm. of A a A. z. z. I. W., vii.—In @ we have 
a large nucleus, to which is fastened a fai/-corpuscle; we have also a small para- 
nucleus, but thjs grows, fais Fik to the nucleus at the end opposite the aż% 
corpuscle, and proceeds to spin a spirallated piece like the middle piece of Figs. 71, 
> ete, = it here has the place of a head-cap, though its functions are DERNE 
nchan 
a 81, a-f. Sperm. of Ae/ix—Platner, A. m. A., xxv.—Here the nucleus buds 
a ucleus, then concentrates, becomes homogeneous, an axis appears, over its 
end the nucleus invaginates itself, while the cytoplasm containing the paranucleus 
spins three spiral filaments; two of these closely invest the axis, the third remains 
free. 
Fic. 82, a~. Sperm. of Cassiopeia —Mereschkowski, A. Z E. G., x.—In ¢ the 
dotted line is a portion of th + ee SN = the “ blastophore,” the protoplasmic 
which d by their heads over its surface. 
os 83, a-e.. EDN of Cucumaria frondosa—Jensen, A. B., iv.—Head- and tail- 
“corpuscles are seen. _Inea middle piece in connection with the ee is 
on is still unfinished. 
vivipara—* hair form” Sepe 
=: two “oe amen "e t periph 
