THE SPERMATOGENESIS OF LEPIDOSIREN PARADOX A. 3 
started preserving testes directly I arrived, and continued 
doing so till February of the following year, and so got a 
series from the torpid dry season state through all the stages 
of preparation for breeding to a stage some months past the 
season for spawning. Although spermatogenesis seems to 
proceed all the year round, still the relative frequency of the 
different stages differs greatly iu testes from the various 
seasons. The breeding habits and methods of hunting 
Lepidosireu have been described by Professor Graham 
Kerr. 
The reason for wishing to obtain material for working out 
the spermatogenesis of Lepidosiren was that this form has 
nuclei of very great size, and in the somatic cells (as deter- 
mined in Professor Graham Kerr’s embryological material) 
the chromosomes are beautifully clear and show very pro- 
nounced size differences. In the course of this work most 
attention has been paid to the method by which the numerical 
reduction of the chromosomes takes place — owing to its 
importance in connecting our experimental knowledge of here- 
dity with the structure and history of the germ-cells. What- 
ever may be the final outcome of the present controversy about 
the relative functions of the nucleus and cytoplasm in here- 
dity, it is well established that many classes of characters are 
distributed alternatively to the gametes, and the only part of 
the hereditary substance which is visibly distributed in a like 
manner are the chromosomes, which are undoubtedly so dis- 
tributed if there has been a previous pairing of correspond- 
ing or “ homologous ” ones. The observations bearing on 
this pairing or conjugation being at present so variously 
interpreted, it becomes of great interest to examine the stages 
in question in a form such as Lepidosiren, which besides 
having cytological elements of great size and distinctness, is 
undoubtedly closely related to the Amphibia, which also, on 
account of their large histological features, have been so much 
worked at, and have (though a single group) furnished 
different workers with every conceivable answer to the reduc- 
tion problem. 
