154 
Katharine Foot and E. C. Strobell 
beeil aiinoiiiiced tliat iiotliiiig like a rest stage iiitervenes between sperma- 
togoiiia and spermatocytcs of tlie Orihoptera and the work of most investi- 
gators woiild tend to indicate tliat it is tlie exception rather tlian the riüe” 
(]). 225). He States however tliat he finds the spermatogonial chroinosomes 
disintegrate and he figiu’es typical stages in the evolution of the hetero- 
type prophase chroinosomes. His figiire 3 shows the thin thread (lepto- 
tene) stage. ln figure 4 the threads are iiiore pronoimced and in figure 5 
a thick spirenie (pachytene) is sliown. 
In oögenesis a post-oögonial rest stage is frequently figimed foUowed 
by typical stages leading iip to the boiiqnet stage, for example Marechal 
(06) in his extensive paper »Sur rOvogenese des Selaciens et de quelques 
untres Chordates« finds a rest stage betiveen the last oögonial division 
and thedeptotene stage. He says: 
»La succession des preniiers stades de ovogenese peut se inarquer 
comiiie suit: repos postovogonial; reconstitution lente des fUaments 
du iioyaii et cominencement de retraction unilaterale; parallelismes ou 
entre-croisenients frequents de ces filanients; synapsis; retraction dis- 
crete, niais surtout Orientation des filanients en bouquet: accolenient total 
ou partiel de ces filanients deux par deux. ä un inoment iiii peii variable; 
spirenie discontinu de filanients epais (stade initial de Rückert) et biva- 
lents; Separation plus ou inoiiis accentuee des moities constitiitives de 
chaqiie Systeme chroniosoniiqiie : noyaux diplote nes; debut du grand 
accroissenient« (p. 185). 
Lerat (05) also finds a postoögonial rest stage in Cyclops strenuus. 
He says: 
»Quoi cpi’il en soit, il est absolunient certain chez le Cyclops que 
la derniere cinese ovogoniale est suivie d’iiii repos et que les filanients de- 
doiibles en long ne representent pas un diaster ovogonial« (p. 169). 
WixnvARTER (00) demonstrated in the rabbit a series of stages lea- 
ding up to the pachytene stage. These he designated as “noyaux proto- 
broques, noyaux deiitobroques, noyaux leptotenes, noyaux synaptenes, 
noyaux pachytenes”. As stated above we have been iinable to find 
evidence of these stages leading up to the pachytene stage in AUolobo- 
phora (Photos 2 to 5) and we have, therefore, in this form only negative 
evidence against any theory which Claims to deterniine the niethod by 
which pseudo-reduction is accomplished. 
^lany authors who find tliat jiseudo-rediiction is established be- 
fore the gi'owth period agree on the important point tliat the chromo- 
sonies retain their individuality throughoiit the growth period and it 
is here that the results of Popoff and others are at variance with 
