LINVILLE: PULMONATE GASTEKOPODS. 217 



ming's fluid has no advantage over other methods, and has the 

 decided disadvantage of causing very great brittleness. Series of sec- 

 tions, even after being mounted and subsequent to the hardening of the 

 balsam, frequently break into small bits under very slight pressure. 

 Perenyi's fluid was used much more successfully. The excessive brittle- 

 ness noticed in the Flemming preparations was not present in those 

 made with this mixture ; moreover, with Perenyi's fluid nuclear struc- 

 tures were well preserved, and when stained the elements came out 

 clearly. Cytoplasmic structures, including the astral rays, were in most 

 cases sharply marked. The methods proposed by Kostanecki und Sied- 

 lecki were not tried with Limax material. In the eggs of Limnaea the 

 nuclear and the cytoplasmic structures were preserved very well by the 

 three methods of Kostanecki und Siedlecki ; of the three, the 3 per cent 

 nitric acid solution gave the best results, the preservation by this method 

 being exceptionally good. 



Heidenhain's iron-hsematoxylin was used exclusively in staining. 

 Slides with sections affixed were immersed in the 2 per cent iron-alum 

 mordant for a period varying from three to twelve hours, and after 

 washing in a gentle current of tap water for several minutes, were 

 placed in the \ per cent aqueous solution of hematoxylin and left for 

 periods varying from eighteen to forty-eight hours. A 2 per cent iron- 

 alum solution was used for decolorizing, the process being carefully 

 watched by frequent examination under a low power of the microscope. 

 In most cases the yolk could be decolorized sufficiently to disclose the 

 ceutrosomes, for example, without decolorizing the centrosomes them- 

 selves. 



A. MATURATION. 

 I. General Account. 

 1. Limax Eggs in the Oviduct. 



My study of the eggs of Limax as they occur in the hermaphrodite 

 gland has been very limited. As far as the position of the nucleus in 

 such eggs is evidence, I cannot discover that the egg has any pre-estab- 

 lished axis, the nucleus being always central. 



The earliest observed stage in the first maturation spindle was seen 

 in eggs found in the oviduct and apparently not long freed from the 

 hermaphrodite gland. Indeed, judging from the proximity of these 

 eggs to the hermaphrodite gland, it seems highly probable that changes 



