128 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
both maturation divisions are held to be equational, since they are 
undoubtedly apparently longitudinal — are far from conclusive. As 
has been so often urged by Montgomery and others, the true inter- 
pretation of the maturation divisions must be sought in synapsis and 
the early prophase, and until these stages are fully elucidated it is 
impossible to arrive at conclusive results as to the significance of the 
two divisions. . From this standpoint a number of recent writers have 
held that when there are two longitudinal divisions one is always re- 
ductional. In the Orthoptera we may have both a transverse and an 
apparently longitudinal division occurring in different chromosomes 
during the same mitosis, although when their previous history is taken 
into account it is evident that both divisions are fundamentally the 
same. 
On the other hand, in the many instances where one transverse 
and one longitudinal division have been described, we may reasonably 
assume that the transverse division is probably reductional, even 
though the early stages in the formation of the bivalent chromosomes 
have not been fully worked out. However, even in such cases there is 
apparently room for doubt, since according to Struckman (:05) a 
transverse division may be equational. - 
Korschelt und Heider (:02) in their extensive review of the subject 
distinguish two types of maturation; the “eumitotic,’ where both 
divisions are equational and the “pseudomitotic,”’ where one is re- 
ductional. ‘The classical examples of the eumitotic type are the 
vertebrates and Ascaris, where, as described by a number of earlier 
investigators, two longitudinal divisions occur. But in the vertebrates 
Montgomery (:03, :04), A. und K. E. Schreiner (:04, :05, :07), 
Farmer and Moore (:05), and Janssens (:05) have found that one 
division is reductional, and in Ascaris Tretjakoff (:04) and Marcus 
(:06) have arrived at similar results, while Boveri (:04) has also 
argued for the probable occurrence of a reductional division in this 
form. 
De Sinéty (:01) has described two longitudinal divisions in various 
Orthoptera and denies that either is a reduction division. His results 
have been criticised at length by McClung (:02) so that it is unneces- 
sary to consider them in detail here. However, I am unable to agree 
in some cases with McClung’s contentions. De Sinéty’s interpreta- 
tion of the maturation divisions appears to be based almost entirely 
on the larger chromosomes, where in some cases both divisions are 
apparently longitudinal. I believe that this author correctly described 
the division of the large ring- and loop-shaped chromosomes and that, 
te ti 
