110 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
three divisions — the head derived from the nucleus, the middle 
part and the tail, both derived from the cytoplasm. 
We owe to La Valette St. George the most satisfactory theory — 
that at least which is now most generally accepted by writers on 
spermatogenesis. To him also we are indebted for the nomenclature 
now most generally used, and that which I have adopted in the present 
work. In a series of articles (“Ueber die genese der samenkorper, ” 
’ 67 , ’ 78 , ’ 86 , ’ 87 ) he has given as a general law, the following suc¬ 
cession of cells with their names, here quoted from Waldeyer: — 
1. Spermatogonien=anfangszellen. 
2. Spermatocyten = produkten der ersten teilung. 
3. Spermatiden=endzellen=produkte der letzten teilung. 
4. Spermatosomen = direkten umformungsprodukten der endzellen 
=samenfaden. 
In the present work it has seemed desirable to define more clearly 
the term spermatogonia and spermatocyte, for it is useful to distinguish 
the primary spermatogonia (those before division begins) and the 
secondary spermatogonia (those which finally form the growing 
spermatocyte). It has also seemed desirable to distinguish more 
definitely than did La Valette St. George between the cyst containing 
spermatogonia, and that containing spermatocytes; hence the terms 
gonocyst and cytocyst introduced in this work. 
Recent literature .— The following statement by Biondr (’ 85 ) 
expresses the condition of the subject at the present time: “Noch 
vor wenigen jahren war es nicht schwierig sieli nach dem stande 
unserer damaligen kenntnisse fiber die spermatogenese eine bestimmte 
und klare vorstellung zu verschaffen. Heutzutage konnen wir das 
nicht mehr sagen; durch zahlreiche neue arbeiten sind zwar unsere 
kenntnisse bezuglich dieses vorganges ausserordentlich vermehrt, 
aber unter bedeutender einbusse an klarheit und einigheit in den 
anschauungen.” In the body of this paper, it has been suggested 
that much of this confusion is due to the naming of accidental and 
transient bodies. This tends to obscure the most essential fact that 
the spermatozoon is merely a greatly elongated cell with centrosome, 
nucleus, and cytoplasm. 
One of the bodies which causes unnecessary confusion is the so 
called nebenkern. The first discoverer of this body is supposed to 
be La Valette St. George. According to Wilson (’02) it was first 
described by Biitschli (’ 71 ). La Valette called it the nebenkorper. 
