THE SPERMATOGENESIS OF LEPIDOSIREN PARADOXA. 25- 
190 and 104 (the egg figured in PL 5, fig. 38) , 220 and 105. 
In PI. 5, fig. 38 the egg is seen filling up most of the tubule in 
which it is situated. The cytoplasm is in the form of a very 
fine mesh work, the strands of which are composed of rows of 
very fine granules. The nucleus is full of a granular or 
flocculent substance, from which the chromatin strands are 
but indistinctly differentiated. 
Besides these three eggs, the same piece of testis contains 
a, few cells connecting them with the semi-resting sperma- 
tocytes with peripherally distributed chromosomes. One of 
these is shown in PI. 5, fig 37. The diameter of the nucleus 
is about 10 /i more than the average spermatocyte nucleus of 
the same stage, being 45 /i. The cell body is 75 n across. 
Not only is the size of the nucleus intermediate between that 
of the spermatocyte and oocyte, but, what is more important, 
its structure is also. The chromosomes, in the somatic 
number, are distributed under the nuclear membrane in a 
precisely similar manner to that shown in PI. 5, fig\ 35, but 
in addition the cavity of the nucleus is filled with a flocculent 
substauce such as we find in the oocyte. For this cause the 
chromosomes — which are also beginning to lose their staining 
capacity — stand out less sharply than in the ordinary 
spermatocytes. The cytoplasm is still like that of the 
spermatocyte rather than the oocyte, showing very little 
appreciable structure. 
The Pre-meiotic (Spermatogonial) Divisions. 
We will consider at this point the early stages of the 
prophase, and their significance in relation to the correspond- 
ing stages of the meiotic prophase. 
The structure of the resting spermatogonial nucleus has 
already been described. It consists of rounded or angular 
blocks of chromatin connected by chromatin bridges and 
linin threads (PI. 1, fig. 2). Preparation for mitosis consists 
in a gradual transformation of these blocks into band-like 
chromosomes. The first stages of this process are seen in 
