612 Wisconsin Academy of Sciences , Arts, and Letters. 
grandiflora (Davis 18), Primula sinensis (Gregory 32), Os- 
munda regalis (Farmer and Moore 23), Aneura pinguis 
(Farmer and Moore 23), and Humaria rutilans (Mliss Fraser 
29). 
Farmer and Mloore (23) have also reported the second con¬ 
traction stage as occurring typically in the ovogenesis of Peri- 
planeta americana, while Moore and Robinson (63) reported 
it in the spermatogenesis of the same species. Farther than 
this practically no attention has been called to this stage in the 
reduction divisions in animals. 
The second contraction stage as described for the above spe¬ 
cies, with the exception of Oenothera, occurs after the stage of 
the uniformly distributed thick spirem. The characteristic 
feature of this stage consists in the massing of a considerable 
part of the spirem in the center of the nucleus from which mass 
more or less irregular loops extend to the periphery. 
The case of Oenothera as reported by Davis (18) differs 
from the other cases above mentioned in that the second synap¬ 
sis is described as following immediately after synapsis without 
the intervention of a stage in which the spirem becomes uni¬ 
formly distributed. 
Farmer and Moore are of the opinion that it is in second 
synapsis that the lateral approximation of the parental chromo¬ 
somes which are to form the double heterotypic chromosome oc¬ 
curs. The parental chromosomes, having previously been con¬ 
nected end to end to form the continuous spirem, now become 
bent together in such a manner that the members of the pair 
come to lie side by side, forming thus the double heterotypic 
chromosome. The significance of the first synaptic aggrega¬ 
tion is left undiscussed by Farmer and Moore, notwithstanding 
the fact that it is one of the most constant and typical stages 
of the reduction divisions. ‘ They describe “the first contrac¬ 
tion stage” as occurring immediately after the formation of the 
thin spirem from the reticulum and the second contraction as 
following after a period of uniformly distributed thick spirem. 
Thus from their descriptions of these stages it seems clear that 
