688 
It is now possible to compare the contents of the spermatozoa 
both in Mammals and Echinoderms, they are: 
Mammals. 
1) The chromatie portion of the nucleus, enclosed in a transparent case 
probably composed of paranuelein and linin 
2) A portion of the spermatid Nebenkern derived from the little wart 
on the nuclear membrane, kytoplasmie in origin 
3) Two centrosomes 
4) A further portion of kytoplasm tail 
head | cephalic 
j portion 
Echinoderms (after FıELD). 
Nucleus hend 
Centrosomes Cephalie 
Bot ae ua | mittiestek Ju 
Kytoplasm tail 
A portion then, of each great structural element of the parent 
cells, is incorporated into the cephalic portion of the spermatozoon (i. e. 
that portion functional in fertilization) and the extrusion during mamma- 
lian spermatogenesis of the residual corpuscle represents merely the 
casting off of superfluous cell substance, and cannot be compared 
in any way whatever to the extrusion of the polar bodies from the 
ovum as supposed by WEISMANnN and others. 
List of References. 
1) Fıeıv, Echinoderm Spermatogenesis. Anat. Anzeiger, Bd. VIII, 1893, 
p. 487—493. 
2) Puatner, Archv. Mikr. Anat., Bd. XXVI, p. 604. 
3) Moore, Qut. Jour. Micr. Sci., Vol. XXXVI, p. 181—196. 
4) Brown, Qut. Jour. Micr. Sci., Vol. XXV, p. 342—367. 
5) Epner, Zur Spermatogenese bei den Säugetieren, p, 237—289. 
6) Weismann, Essays on Heredity. Clarendon Press, 1889, p. 220—223. 
7) Benpa, Ueber die Histiogenese des Sauropsidenspermatozoons. Verhdlg. 
Anat. Gesellschaft, Bd. 6, 1892. 
Die Herren Mitarbeiter werden dringend gebeten, thre Wiinsche 
bez. der Anzahl der ihnen zu liefernden Sonderabdriicke auf das 
Manuscript zu schreiben. Die Verlagshandlung wird alsdann die 
Abdrücke in der von den Herren Verfassern gewünschten Anzahl 
unentgeltlich liefern. 
Erfolgt keine andere Bestellung, so werden fünfzig Abdrücke 
geliefert. 
Frommannsche Buchdruckerei (Hermann Pohle) in Jena, 
