Nov., 1914.] Starnens of Smilax herbacea. 363 



order that they may have a definite position in the spirem during^ 

 the synaptic stages when the bivalent chromosomes are formed 

 by an end to end pairing and later longitudinal folding of the 

 chromatic elements. By many investigators "synapsis" is used 

 to designate the period of contraction which very generally 

 appears in the earlier stages of reduction. But it is much better 

 to use the term synizesis as was suggested by McClung and 

 adopted by Schaft'ner in the more recent of his cytological papers. 

 By eliminating this confusion of terms such expressions as "synaptic 

 mates," etc. in relation to the chromosomes, become intelli- 

 gible without further explanations. 



The protochromosomes do not retain a definite shape, but in 

 a short time there is an apparent elongation of each mass and 

 a tendency for the delicate connecting linin threads to become 

 thicker as the elongation continues. (Figs, -i, 5, 6). vSoon no- 

 traces of the flaky masses are left, but instead there is a very 

 delicate continuous spirem which can be traced for long distances- 

 in many of the sporoc3^tes without finding any free ends. The 

 free ends in most cases can all be accounted for by their having 

 been cut in sectioning. (Fig. 7). 



There is now a perceptible enlargement of the nucleus, which 

 appears very turgid; as a result of this enlargement the very 

 delicate spirem becomes loosened from the nuclear membrane 

 and does not appear to be so uniformly arranged about the 

 periphery as before, but has the appearance as if it had been 

 treated with some plasmolizing reagent. (Fig. S). 



By this time there is usually one large nucleolus present, 

 which very seldom appears in a central position and sometimes 

 there are also dark staining gratiules in the nuclear cavity which 

 in all probability are minute nucleoli. Miss Elkins noted this 

 same fact in her study of Smilax herbacea. 



The spirem and granules in the earlier division stages show no 

 evidence of a double character. Soon after the spirem has 

 become loosened from the nuclear wall, there is an irregular 

 massing of the thread, which either may or may not e.iclose the 

 nucleolus. (Figs. 9, 10, 11). The types of contraction are not 

 always the same and there was no evidence that synizesis is an 

 actual stage in the reduction division. As previously mentioned 

 Lawson considered this condition to be due to a period of growth 

 in the nucleus, there would be thus no actual shrinking of the 

 chromatin, but there can be no question that in the preparations 

 studied there was a considerable actual contraction. Schaffner 

 (15) regarded this condition as an artifact on account of experi- 

 ments tried with living material of Agave virginica and the 

 reactions also obtained by the treatment with different reagents 

 which caused plasmolysis to take place in the vegetative cells, 

 giving the spirem much the same appearance that was found in 



