246 Thomas H. Montgomery, Jr., 



was very slight, aud as follows. The cleavage anaphases usually 

 exhibit every two nuclei of identical appearance (Fig-, 39, a second 

 cleavage spindle). In each of two eggs of five and a quarter hours, 

 representing the commencement of the 4cell stage, each egg with 

 two nuclear anaphases, one nucleus of one of the anaphases has 

 apposed to its outer surface a mass staining like chromatin. The 

 whole of one of these anaphases is drawn in Fig. 40, and the half 

 of the other in Fig. 41. The extranuclear bodies are much smaller 

 than the nuclei and are alike in the two cases. They may represent 

 either one of two conditions: (1) chromosomes abnormally separated 

 from the others; or (2) a normal process of chromatin extrusion not 

 exactly comparable to the chromatin diminution of Ascaris. In no 

 other cells of the 2cell, 4cell or 8cell stage, either in tiie anaphase 

 or the rest condition, were bodies like these found, so that it is fair 

 to conclude that the two eggs first mentioned were abnormal. 



VI. Polyspermy. 



This appears to be quite frequent, and when it occurs all the 

 sperm nuclei are alike in size and appearance, each also is the 

 centre of a cytoplasmic accumulation but never do two occur within 

 the same cytoplasmic mass. Further, only one of the sperm nuclei 

 comes to lie close to the egg nucleus within the centre of the egg, 

 while the others remain more excentric or even superficial in posi- 

 tion. Figs. 27a — 27d show four nuclei from the same egg of the 

 age of two hours and forty minutes: of these 27a and 27b are the 

 egg and sperm nucleus at the centre of the egg; while 27c is the 

 nucleus of the second polar body, and 27d a supernumerary sperm, 

 both of these close to the surface of the egg. Then in the case of 

 another egg, of the age of three and a quarter hours. Fig. 30 shows 

 the egg and sperm nuclei at the centre, and Figs. 31a— 31c three 

 supernumerary sperm nuclei. More than three such nuclei were not 

 seen in any egg. 



As to the fate of these supernumerary sperm nuclei, I can only 

 state that they continue to lie superficial or excentric, and that 

 mitoses (Figs. 42, 43) occasionally found at the surface in the 2cell 

 and 4cell stages are the divisions of either accessory sperms or of 

 second polar bodies. In the anaphase of such a mitosis drawn in 

 Fig. 43 just 12 chromosomes are seen in the one daughter plate 

 and approximately that number in the other, accordingly these super- 



