THE SPERMATOGENESIS OF LEPIDOSIREN PARADOXA. 
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eyepieces of a higher power) in unravelling a complicated 
spireme or a nucleus full of chromosomes. 
The Number of Chromosomes. 
The somatic number of chromosomes is thirty-eight. Both 
this and the reduced number, nineteen, have been counted 
over and over again in the meiotic nuclei. Murray gave the 
somatic number as probably thirty-six, which is as near the 
right number as could be expected to be arrived at from the 
somatic mitoses with their long chromosomes. 
The Germinal Epithelium. 
The testes are composed of numerous convoluted tubules 
which in a transverse section appear cut through in every 
direction. These tubules are lined with the germinal 
epithelium, which, in an adult breeding Lepidosiren, consists 
of spermatogonia of all orders, spermatocytes and spermatids, 
mixed up together with very little arrangement. There is no 
definite layering of the cells of the successive generations, 
but on the whole those of the later orders are nearer the 
lumen of the tubules than those of the earlier ones. Still, it 
is impossible in most cases to say from its position in the 
germinal epithelium to what generation a given cell belongs. 
Also all the tubules throughout the whole length of any testis 
present the same stages. Nevertheless the seriation has not 
been a matter of much difficulty. The testis tubules branch 
and wind about in an extremely complicated way, and at the 
blind end of the branches one always finds a solid, though 
generally very small, mass of spermatogonia. I also got one 
immature male, just after the beginning of the rainy season 
but before the fish had come out of the ground, in which the 
testis consists almost entirely of spermatogonia with very few 
primary spermatocytes and one fully formed spermatozoon to 
every score or two of sections. Another useful specimen was 
an adult male preserved at the same season in which the testes 
