31 8 LELIA T. PORTER. 



/ 



the larger chromosomes are seen to be pulled apart. As they 

 divide and separate they are usually still connected by two thick 

 threads (Figs. 6, 7, 9). These fibers stain deeply with hsematoxy- 

 lin but are lost sight of as the chromosomes are pulled farther 

 apart and the cell wall begins to constrict. There is no sign of a 

 zwischenkdrper as described by Paulmier for Anasa. Each of 

 the two resulting secondary spermatocytes (Figs, n, 12, 13) 

 contains six chromosomes in the form of dyads and one monad, 

 the accessory. There is no trouble identifying the accessory 

 because of its size and position. 



SECOND SPERMATOCYTIC DIVISION. 



The second division follows directly upon the first without 

 any resting stage. In the equatorial plate of the second division 

 the chromosomes are arranged in the characteristic ring of six 

 with the smallest chromosome in the center. In the case of 

 Anasa tristis Paulmier finds no such regular arrangement though 

 he says the small chromosome generally lies in the center. The 

 chromosomes now arrange themselves on the middle of the 

 spindle and very soon the accessory is seen to leave the group 

 and pass undivided in advance of the others toward one of the 

 poles (Figs. 14, 16, 17, 18, 19, 20). In Anasa the accessory lags, 

 and is not drawn toward one of the poles until the other chromo- 

 somes have practically come to the end of their movement. 

 The remaining dyads then divide apparently in the same order 

 as for the first division, the smallest leading (Figs. 15, 17, 19). 

 These then pass to opposite poles and the cell constricts in the 

 middle. The resulting cells are smaller than those of the first 

 division, half of them containing seven chromosomes, and half 

 six (Figs. 21, 22, 23, 14). The chromosomes of these spermatids 

 have the same characteristic arrangement as those of the primary 

 and secondary spermatocytes, one half of them having a ring of 

 six with a small one in the center and the other a ring of five 

 with the small one also in center. There is a typical massing 

 of the chromosomes in the spermatid before the nuclear wall is 

 formed. 



The spindle of the second spermatocyte is similar in shape to 

 that of the first, being rather broad and thick at the initiation 



