486 D. H. WENRICH 



as, for example, one cleft for number 12 in cell D, two clefts for 

 number 11 ill cell D, two clefts for number 10 in cell C, and in 

 the case of the atelomitic member of number 8 the cleft shows 

 very plainly in cell D. Clefts are like\\dse indicated for number 

 7 in cells C and D, and still more plainly in the metaphase cells, 

 E and G. These clefts or constrictions appear to correspond in 

 all respects to those found in the ateloftiitic chromosomes of 

 Chorthippus. 



Chromosomes 5, 6, and 7 are somewhat similar in organiza- 

 tion, each possessing polar granules at both ends. This gives 

 rise to some uncertainty as to identity, especially in cells B 

 and C. In cell A the differences in length are more apparent. 



Number 4 in cells A, B, and C, and number 8 in cells A and 

 B are readily identified by the pecuhar clusters of granules (c) 

 attached to them. In the later stages these disappear and 

 this gives rise to some difficulty in identification in the case of 

 chromosome 8. Number 4, however, possesses an additional 

 means of identification by reason of its staining power which is 

 constantly gTeater than in the other euchromosomes. 



In spite of the difficulties of identification, it is felt that with 

 all the chromosomes present in each cell, and with a careful 

 consideration of the size and structure relations of the various 

 chromosomes, very few mistakes in serial arrangement have 

 been made. 



c. The evidence on synapsis. The evidence for parasynapsis, 

 as presented on plate 2 is of the same nature as that for Chor- 

 thippus, and consists in the facts: (1) that all the euchromosome 

 pairs, irrespective of the point of spindle-fiber attachment, 

 come out of the growth period as longitudinally split, attenuated 

 threads, and (2) that from these spUt thi'eads tetrads arise by 

 the formation of the secondary longitudinal spht. Figure 21, 

 plate 3, gives the evidence for parasynapsis as it occurs in the 

 lepto-zygotene stages and the conditions shown are quite similar 

 to those already described for Chorthippus and shown in figures 

 1 to 4. Figure 21 does not represent nearly all of the chromatin 

 threads in the nucleus and is partially diagi-ammatic. However, 

 the condition indicated — namely, the presence of double threads 



