Katharine Foot and E. C. Strobell 243 



PiioTO. 106. X 1000. Section showing the centriole at the peripheral pole of 

 a first maturation spindle, of an oocyte from the receptaculum ovorum. Fix- 

 ative corrosive acetic (10 per cent). Stain, iron hsematoxylin followed by 

 dilute Bismarck brown. 



Photo. 107. x 1000. Section of the spindle of one of two small cells of a 

 three celled egg from the cocoon, showing one of the two centrioles. Fixative, 

 chromo-acetic. Stain, iron hseniatoxylin. 



Photo. 108. x 710. Section showing the centriole at lower pole of the 

 second maturation spindle of a fertilized oocyte from a cocoon. F'ixative, 

 Merkel's fluid. Stain, iron hematoxylin. 



Photo. 109. X about 1100. Section showing centriole at the lower pole of 

 a second maturation spindle of a fertilized oocyte from a cocoon. Fixative 

 chromo-acetic. Stain, iron hsematoxylin. 



Photo. 110. x 710. Section of a second cleavage spindle of an egg from 

 a cocoon. Both centrioles are shown though they are not on exactly the same 

 plane. Fixative, chromo-acetic followed by osmic acid. Stain, iron haema- 

 toxylin. 



PLATES VII, VIII and IX. 



The preparations shown in the photographs of these plates are from oocytes 

 from the receptaculum ovorum (except Photo. 128), and were obtained by the 

 method described on p. 200. 



The preparations were stained with Bismarck brown. 



Magnification of all the photographs, 1000 diameters. 



Photos. Ill and 113. Two germinal vesicles each showing a principal nu- 

 cleolus, one accessory nucleolus and a fine chromatin thread. 



Photo. 112. Germinal vesicle showing a pathological aggregation of the 

 chromatin. 



Photos. 114 and 115. Two germinal vesicles showing each a principal nucle- 

 olus and a longitudinally split spireme. In Photo. 114 there is one, and in 

 Photo. 115 there are two accessory nucleoli. 



Photos. IIG to 124. Germinal vesicles showing different forms of the eleven 

 bivalent chromosomes immediately after the transverse division of the spi- 

 reme, in Photo. 116, two of the bivalent chromosomes are still attached end to 

 end. Nearly all these preparations show a longitudinal split in some of the 

 chromosomes, and in Photos. 116, 118, 121, 122, 123 and 124 both the principal 

 and the accessory nucleoli are present. 



Photos. 125, 126, 127, 129 and 130 show the eleven bivalent chromosomes 

 arranged with more or less regularity in the equator of the first maturation 

 spindle. For detailed description of these photographs, see p. 217. 



Photo. 128. The eleven chromosomes nearly in the equator of the first 

 maturation spindle of an oocyte from an immature cocoon. 



