238 Thomas H. Montgomery, Jr., 



The species examined was Theridium tepidariorum C. Koch^ 

 one of the most abundant and commonest species of its family. 

 The eggs were secured by having the spiders raise them in captivity, 

 the only method by which one can obtain accurately timed stages. 

 In three preceding papers (1903, 1906, 1907) T have described how 

 the male charges his palpi with sperm, the processes of copulation, 

 oviposition and cocooning, also the occurrence of a probable size 

 dimorphism of the eggs, therefore these subjects need not be treated 

 at tliis place. 



It is a great disappointment to me that the results here 

 presented are so meagre and with so little of broader importance, 

 and this notwithstanding that I have given the subject a great 

 amount of time and diligence. The aranead egg is clearly a difficult 

 object to investigate. A very complete series of stages was collected 

 from the moment of oviposition up to the age of several days, but 

 I was so unfortunate as not to obtain eggs from the oviducts and 

 accordingly cannot describe the first entrance of the sperm or the 

 complete formation of the first polar spindle. Most of the changes 

 have to be studied upon sections, but I have not often secured 

 unbroken sections and never complete series of such. Possibly with 

 a better method than the usual paraffine imbedding one would get 

 better preparations. 



Only accurately timed eggs were used, timed from the moment 

 of oviposition; all the eggs within a given cocoon are of approxi- 

 mately the same degree of development. The cocoons were opened 

 and the eggs dropped directly into the fixative, half the eggs from 

 each cocoon being preserved in one fixative and half in another. 

 These were Gilson's fiuid, equal parts of chloroform, absolute alcohol 

 and glacial acetic acid with sublimate to saturation; and a fluid 

 used by success by Towee for insect eggs, 95 parts of a solution 

 of corrosive sublimate in 357o alcohol, 2 parts of glacial acetic acid, 

 and 3 parts of nitric acid; the latter mixture was used hot, and 

 the former cold. Tower's solution is excellent up to the time of 

 cleavage, but strangely enough seldom gives good fixation of the 

 nuclei and mitoses during cleavage. Gilson's fiuid is excellent for 

 the nuclear division figures in all stages, and has the further ad- 

 vantage of separating the outer membrane from the egg so that it 

 may be easily dissected away ; it has the disadvantages of sometimes 

 distorting the general shape of the egg, and, especially in the case 

 of eggs within half an hour after oviposition, of separating the outer 



