CHROMOSOME STUDIES 243 



157, 158), that one cannot avoid believing them identical, though 

 they are compound in one genus and simple in the other. The 

 connections at the apices of the V's, where the spindle fibers 

 become attached, apparently make no difference in the be- 

 havior of the rod limbs of the V's in the processes of conjuga- 

 tion and disjunction. The limbs of the 7-11 pair of V's may 

 form rods, crosses, horseshoes, or rings of various sorts just as 

 readily as if they were separate chromosomes. The compound 

 nature of the large chromosomes was evident. Having this 

 in mind, and knowing that in parasynapsis the first parts of 

 chromosomes to pair are the distal ends (in the cases of V's 

 the ends of the limbs), my opinions in regard to the time of 

 reduction were seriously changed when I found the interlock- 

 ing that I have described and shown in figures 163 and 177. 

 It was then evident to me that the gaping spht between the halves 

 in the middle of paired loops was, most likely, the space be- 

 tween chromosomes which had paired. Following this split 

 through the series of prophase chromosomes up to the first 

 maturation division, I found it to be the primary split and there- 

 fore the reductional division. In both species of Syrbula the 

 prophase tetrads, consisting of rods, crosses, horseshoes, and 

 rings, appear and behave just like the 5, 7, 8, 9, 10, and 11 parts 

 of the compound chromosomes of Chorthippus. There is good 

 reason to believe that in Syrbula admirabilis, as in Chorthippus, 

 the first maturation division is reductional. I therefore must 

 admit that in my paper on Syrbula I was wrong in regard to 

 the absence of parasynapsis and to the time of- reduction, and 

 that, so far as concerns the time of reduction, I shall have to 

 differ with McClung and those of his students who have taken 

 the same stand upon this question. 



A second case in which it seems to me that the first matura- 

 tion division is clearly reductional is that of the single V-chromo- 

 some of Jamaicana subguttata (my figs. 198, 199), which sepa- 

 rates from its two unequal rod-mates in this division. Sperma- 

 togonia of this animal show thirty-two rod-shaped autosomes 

 in addition to one slightly unequal armed V autosome and 

 the large sex chromosome. The first maturation division (fig. 



JOURNAL OF MORPHOLOGY, VOL. 27, NO. 2 



