EGG OF ALLOLOBOPHORA FCETIDA. 551 



EXPLANATION OF PLATE XLIV. 



The photos of this plate are from preparations of eggs found in cocoons where 

 the slime tube is still intact or is just beginning to degenerate. 



Photos 63-77, X 2S6 diameters. 



Photos 7S-S5, X 660 diameters. 



All the preparations were stained with iron-haematoxylin, except No. 82, which 

 is unstained. 



Photos 63-77, fifteen serial sections (3/11) of a mature egg, the pronuclei in early 

 stages of formation. At this stage archoplasmic masses are distributed around the 

 entire periphery of the egg, later accumulating at two definite areas and forming 

 the polar rings (Photos 78-S5). Fixative, chromo-acetic, followed by osmic acid. 

 X 2S6 diameters. 



Photo 78, section {3;u) of a mature egg. The peripheral archoplasm has con- 

 centrated at nearly opposite poles ; but the polar rings are not yet complete and 

 the pronuclei have not reached more than half their maximum size. The condi- 

 tions surrounding the pronuclei are probably abnormal ; but the rest of the 

 cytoplasm closely resembles that seen in the living egg at this stage. Just to 

 the left of the upper thickening of the right polar ring, several hyaline globules 

 appear to be fixed in the process of fusing. This has been seen repeatedly in the 

 living egg (cf. Photo 59, PI. XLIII, for an intermediate stage between this egg (78) 

 and Photos 63-77). Fixative, Flemming's fluid without acetic acid. 



Photo 79, section (3/i) of an egg at about the same stage of development 

 shown in Photo 78. The pronuclei have increased in size and small masses of 

 archoplasm surround them. The configuration of the cytoplasm of the two sections 

 is quite different ; the egg of Photo 79 having been fixed in corrosive sublimate 

 and the egg of Photo 78 in Flemming's fluid without acetic acid (cf. Photo 84 for 

 the granular structure of the archoplasm of the polar rings). 



Photo 80, section (3 it) of an egg at a slightly later stage of development than 

 that of 79 ; the pronuclei have increased in size, although they have not yet reached 

 their maximum growth, and the archoplasm of the polar rings has aggregated into 

 more compact masses. The polar rings not being at exact opposite poles, only a 

 small piece of the left ring is in the section. A few small masses of granular 

 archoplasm are near the pronuclei, and archoplasmic granules can be seen scat- 

 tered through the cytoplasm. Fixative, corrosive subhmate (cf. Photo 84 for the 

 granular structure of the archoplasm of the polar rings). 



Photo 81, vignetted section (3/ii) of an egg at nearly the same stage of develop- 

 ment as that of Photo 80. In this egg the pronuclei appear to have reached their 

 maximum growth (they are not shown in this section). This photo is one of a 

 number taken to show that the form of the rings is not constant — a comparison 

 of the rings of Photos 80, 81, 83, and 85 will illustrate this point which was made 

 in an earlier paper.i Fixative, chromo-acetic, followed by osmic acid (cf. Photo 84 

 for the granular structure of the polar rings). 



• '* No two rings of either pole have been found exactly alike. The light areas in their center differ 

 in size and shape, and the number and form of the smaller light areas, which occur through the mass 

 of the rings, are by no means constant. The outer edges of the rings are never exactly alike in any 

 two specimens," Foot (8). 



