250 Thomas H. Montgomeky, Jr., Maturation and Fertilization in Theridium. 



Figs. 16 — 18. Surface views of second polar spindles at 40 minutes, 

 1 hour, and 1^/^ hours respectively. 1800:1. 



Fig. 19. Surface view of second polar spindle, 1 hour. 1800 : 1. 



Fig. 20. Surface view, obliquely from the pole, of the two chromo- 

 some plates of a second polar spindle, 1 hour. 1800 : 1. 



Figs. 21, 22. Optical sections of two eggs, from surface views, of 

 ca. 1^/2 hours, showing first and second polar bodies and egg nuclei. 

 1030: 1. 



Fig. 23 — 25. Sperm nuclei aged 15 minutes, 1 hour, two hours. 

 2400 : 1. 



Plate 5. 



Fig. 26. Pronuclei in surrounding cytoplasm, 2^/2 hours. 2400 : 1. 



Figs. 27a — d. Nuclei from the same egg of 2 hours, 40 minutes, 

 a being the egg nucleus, b the central sperm nucleus, c the nucleus of 

 the second polar body, and d a supernumerary sperm nucleus. 2400 : 1. 



Fig. 28. Pronuclei, 2 hours, 40 minutes. 2400 : 1. 



Fig. 29. Pronuclei within enveloping cytoplasm, 2 hours, 40 minutes. 

 2400 : 1. 



Fig. 30. Pronuclei, 3^/^ hours. 2400 : 1. 



Figs. 31a — c. Supernumerary sperm nuclei from the same egg as 

 Fig. 30. 2400 : 1. 



Fig. 32. Prophase of pronuclei, 3 hours. 2400:1. 



Fig. 33. First cleavage spindle, 3^/2 hours. 2400 : 1. 



Fig. 34. Portion of another first cleavage spindle of the same age. 

 2400 : 1. 



Figs. 35, 36. Cleavage spindles of an egg of the 4cell stage, 6^4 

 hours. 2400:1. 



Fig. 37. Later cleavage spindle of the 4cell stage, 6^/^ hours. 

 2400: 1. 



Fig. 38. Pole view of one chromosome plate of an anaphase of 

 the 4cell stage, 6^/^ hours. 2400 : 1. 



Fig. 39. Second cleavage spindle, 5^/^ hours, with the surrounding 

 cytoplasm. 2400 : 1. 



Fig. 40. Later second cleavage spindle, 5^/^ hours, the outline only 

 of the cytoplasmic envelope drawn. 2400 : 1. 



Fig. 41. One daughter nucleus with the extranuclear body of an 

 anaphase of the same age and stage as Fig. 40. 2400: 1. 



Figs. 42, 43. Superficial mitoses of supernumerary sperms or second 

 polar bodies, 4 and 5 hours respectively. 2400 : 1. 



Fig. 44. Adult epigynum, receptacula seminis and their tubes seen 

 from ventral view on a preparation cleared in balsam. 290: 1. 



