THE SPERMATOGENESIS OP LEPIDOSIREN PARADOXA. 35 
troclia (Korsclielt’s account; in this case also the pairing is 
extremely loose). 
The separation and second pairing of the ex-conjugants 
gives indirect support to the view that the first pairing was 
by parasyndesis. For if not — if, that is to say, the reduced 
number of chromosomes in the bouquet stage has been 
brought about by an end-to-end junction of the chromosomes 
— it seems extraordinary that they should separate, only to 
come together again in exactly the same way. On the other 
hand, if the original conjugation were by parasyndesis a 
possible explanation presents itself, and this is connected 
with the important question of the function of chromosome 
conjugation. It was suggested by the Schreiners in an 
interesting paper that this function is a double one. The 
intimate fusion during the prophase (parasyndesis) is to be 
considered as a physiological process of a “ rejuvenescing* ” 
nature, in which interchange of substance takes place. After 
conjugation, that is, in strepsinema, the ex-conjugants separate 
physiologically, but remain approximated or even united by 
their ends or elsewhere in order to ensure the characteristic 
distribution of the chromosomes in the reduction division. 
Thus the separation of homologous chromosomes to different 
gametes, often considered the whole object of conjugation, is 
only one of two independent functions. The case of 
Lepidosiren supports this view. If the whole object of 
conjugation were to bring about the separation of homo- 
logous chromosomes in metaphase I, it would appear incon- 
ceivable why the chromosomes, having once paired (and that 
they are of the reduced number in the bouquet stage is a 
matter of observation, independent of any view as to how the 
pairing has taken place), should separate only to pair again. 
The fact that in certain parthenogenetic eggs (Cladocera, 
Kuhn) appearances of parasyndesis are found, although in the 
equatorial plate of the maturation division the somatic number 
of chromosomes appears, has been taken by some as a final 
refutation of the theory of parasyndesis, e. g., Goldschmidt 
says : ec . . . zum Schlusse noch eines — aucli bei partheno- 
VOL. 57 , PART 1 . NEW SERIES. 3 § 
