358 
The Ohio Naturalist. 
[Vol. XV, No. 1, 
In my studies, therefore, careful observations of the spirem 
were made with the view of determining whether there is a con¬ 
tinuous thread or whether there are a number of short individual 
threads interwoven but distinct as described by Lawson and others 
in a number of cytological studies of plants more or less closely 
related to S. herbacea. 
The exact.manner of chromosome formation was also studied 
to determine whether they were the result of a looping and a 
later longitudinal folding, or if there was simply a transverse 
constricting and breaking apart of the spirem to form the chromo¬ 
somes as described by Miss Elkins in Smilax herbacea. 
It was with these points in view that this study and review 
of the necessary literature was taken up under the guidance of 
Prof. John H. Schaffner, whose assistance and advice was found 
to be of inestimable help in all work undertaken with him. 
GENERAL CONSIDERATION OF PAST LITERATURE ON THE SUBJECT. 
Since in recent years all except the latest papers have been 
repeatedly reviewed, it is not considered necessary to refer to any 
except such as have a very direct bearing on the matter in hand. 
Those dealing with plants closely related to Smilax herbacea are 
however included so far as they are available for study. 
Miss Elkins in her paper, “The Maturation Phases in Smilax 
herbacea,” states that she did not find a distinct reticulum in the 
microsporocytes, and often the chromatin bodies were in pairs 
or fours scattered through the finely granular meshes. According 
to her account the multinucleolate condition is the rule rather 
than the exception and often the nucleoli have papillate pro¬ 
jections which are present quite late. At “synapsis” or contrac¬ 
tion there is never more than one nucleolus present which condition 
is brought about by the union of the nucleolar elements, but often 
there are dark staining bodies left in the nuclear cavity. .She 
also found that the nucleolus disappears at the metaphase just 
as Gates found for Oenothera rubrinervis. In the presynaptic 
stages, the linin meshes are said to contract, drawing the chro¬ 
matin material together, while the nucleolus is at one side pro¬ 
jecting from a mass of threads. It is during this period that 
she found the chromatin becoming arranged into an interwoven 
beaded filament. The appearance of the nucleus after synizesis 
is stated to be quite different from its previous condition, the 
chromatin emerging as a homogeneous filament. It is also 
vaguely suggested that this may facilitate proper placing of 
the paired parental elements in the chromosomes in the spirem. 
She says that the chromosomes do not appear as definitely united 
until the segmentation of the spirem. After synizesis the spirem 
is a fairly thick thread, slightly beaded, but in a short time becomes 
homogeneous. She observed that the double character of the 
