80 bulletin: museum of comparative zoology. 



same orientation as the chromosomes of the preceding telophase. They 

 appear to be composed of a very much contorted thread made up of 

 chromatin granules imbedded in a linin matrix. This thread is so- 

 contorted and bent upon itself that it is impossible in this species to 

 determine whether each mass is composed of one or several distinct 

 threads. The structure of these masses can be made out much better 

 in Chortophaga viricUfasciata, in the account of which they will be 

 described in detail. It is sufficient here to state that they are much 

 more distinct and widely separated in this species than in any other, 

 while their number is approximately the same as that of the sperma- 

 togonial chromosomes. We may conclude, then, that each mass of 

 chromatin is a univalent autosome, which in Chortophaga can be 

 seen to be transformed, by a sort of unraveling process, into a chroma- 

 tin thread. In Dissosteira it is impossible to make out satisfactorily 

 the formation of the threads, but in the next stage (c) the nucleus 

 contains probably several much convoluted threads (Figs. 29, 30) 

 composed of linin, in which small rounded chromatin granules are 

 imbedded at short, and fairly regular intervals. Extending out from 

 each thread, and connecting it with adjoining threads, are fine linin 

 fibrils. It is impossible at this stage to determine by observation 

 whether there is one or a large number of chromatin threads, but, for 

 reasons given above, I believe that there are reallv a number of distinct 

 threads, and that there is at no time a continuous spireme. During 

 this stage one or two small plasmosomes, staining deeply with Bor- 

 deaux, appear in the nucleus. 



The next stage (d) is characterized by polarity in the arrangement 

 of the spireme. In favorable cases it can be plainly seen that the 

 threads are now attached at one side to the nuclear membrane (Figs. 

 31, 32). Probably the attachment takes place somewhat earlier, 

 but is not distinguishable on account of the more tortuous course taken 

 by the spireme threads. When this polarity of the spireme first 

 becomes evident the threads still take such a tortuous course through 

 the nucleus that the polarity is distinguishable only near the region 

 where the threads are attached to the nuclear membrane. However, 

 during the latter part of this stage the polar arrangement of the threads 

 becomes much more distinct; but it is never as marked in this species 

 as in some other Orthoptera. A careful study of the nucleus at this 

 stage shows that the spireme is really in the form of loops attached 

 by their free ends to the nuclear membrane at a common point. At 

 first glance the number of loops at this time appears to be consid- 

 erably greater than at a somewhat later stage. However, I believe 



