THE SPERMATOGENESIS OF AGALENA N.KVIA. 147 



In Agalena, the widening of the longitudinal split at this stage 

 js of universal occurrence in the ordinary chromosomes and is of 

 first importance as a foreshadowing of the opening out of the 

 single V-shaped chromosomes to form double V's, which is the de- 

 finitive form of every ordinary chromosome. Furthermore Mont- 

 gomery's own figures of the telophase show many V-shaped 

 chromosomes and indicate that in Lycosa, also, the chromosomes 

 of the metaphase are double V's. On examination of my own 

 sections of Lycosa, I find this to be true. 



5. In Lycosa " there is no intermediate cell-plate formed after 

 the reduction division but after all other divisions." 



In Agalena, the intermediate cell-plate is always found at this 

 stage and is often conspicuous. 



6. In Lycosa "the two univalent heterochromosomes conju- 

 gate side to side though their ends directed toward the distal 

 nuclear pole are in closer touch than their opposite ends, in con- 

 trast to the behavior of the other chromosomes." 



In Agalena the heterochromosomes unite, apparently, into 

 a single mass and the union usually begins at the ends directed 

 toward the central pole. 



7. In Lycosa " the mode of division of the bivalent hetero- 

 chromosomes was not positively determined" but in its forma- 

 tion " there is some evidence that the heterochromosome may 

 behave like the others during the maturation mitoses, namely, 

 that it may undergo a reductional division in the first and an 

 equational division in the second mitosis. And we can say posi- 

 tively that the whole bivalent heterochromosome does not pass 

 undivided into one of the second spermatocytes." ( ! ) 



In Agalena and several other genera the heterochromosomes 

 clearly pass undivided into the secondary spermatocytes and in 

 Agalena, at least, they are equationally divided in the second 

 maturation mitosis. 



Rosenberg's beautiful work ('05) on the spermatogenesis of 

 the Arachnida is based chiefly upon a study of Lycosa and his 

 observations begin with the telophase of the second maturation 

 division, his work being largely confined to a detailed study of 

 the transformation of the spermatid into the mature spermatozoon. 

 Taking Wagner's results upon Agalena as a starting point, he 



