576 Thbophilus s. Painter, Spermatogenesis in spider. 



Figs. 102 to 111 are all drawn to a very large scale. The pro- 

 portional size of the threads, however, is accurate. The rest of the 

 figures 2500: 1. 



Fig. 102. Diplotene-thread of Dolo7nedes fonianus. 



Fig. 103. Same showing the beginning of the twist. 



Fig. 104. Same showing still more twisting. 



Figs. 105 to 107. Showing untwisting of the thread. 



Fig. 108. Later stage of same. 



Fig. 109. Same. 



Fig. 110. Still later stage when the autosomes are beginnig to take 

 on the form which they will have during the division. 



Fig. 111. Fully formed autosome of Dolomrdcs funtanus. 



Fig. 112. First division in Bolomedes fontanus. 



Fig. 113. Equatorial view of same. 



Fig. 114. "Rest period" for Lycosa communis. 



Fig. 115. First division in Lycosa communis. 



Fig. 116. Equatorial view of same. 



Fig. 117. First division in Oxyopes salticus. 



Plate 34. 



The drawings in this plate are drawn to a very large scale. As 

 explained in the text, measurements were made of the chromosomes by 

 means of a micrometer eye-spiece. 



Fig. A. Autosomes from spermatogonia! prophase in Maevia vittata. 



Fig. B. Accessory chromosome from Maevia vitlata, "gray variety", 



Fig. C. Same as above. 



Figs. D, E, F, G. Show the two types of autosomes which occur 

 during the early prophase in the first division of Maevia vittata, "gray 

 variety". 



Figs. H, I, J, K. Show the way in which these autosomes divide. 



Figs. L, M. Autosomes from the second division of Maevia vittata, 

 "gray variety". 



Fig. N. Showing shapes of autosomes in first division of Amaurohius 

 .sylvestris. 



Fig. 0. Showing the form of the centrosomcs taken from the same 

 cell in Amaurohius sylvestris. 



