140 David Day Whitney 



were laid, were put into Schneider's aceto-carmine for about thirty 

 seconds and then into a water-glycerine solution (i drop in 5 cc. of 

 water). The blastomeres become separated and the polar bodies 

 can be readily seen. 



Ill FEMALE EGG 



The female egg is easily distinguished from the male egg by its 

 larger size and is never mistaken for the winter egg which may 

 be of equal size, but has a much thicker envelope around it, besides 

 containing the conspicuous sperm nucleus. 



In the female parthenogenetic egg the number of chromosomes 

 was never definitely determined but many spindles in metaphase 

 were seen in side view, containing numerous chromosomes (20 to 



&'4 •>- » 



A *•• 



Fig. I Female parthenogenetic egg. A, equatorial plate of the polar spindle, showing twenty- 

 three to twenty-five chromosomes; B, prophase of polar spindle, showing twenty-two chromosomes. 



30). In one polar view of a metaphase twenty-five chromo- 

 somes were seen, Fig. i, A. In a prophase twenty-two dumb-bel 

 shaped chromosomes were seen in one section (Fig. i, B) and in 

 the adjoining section there were four other dumb-bell shaped 

 chromosomes together with one that was not constricted. No 

 anaphase or telophase stages were found although hundreds of 

 eggs were examined. Lenssen found the chromosomes somewhat 

 scattered about on the equator of the maturation spindle and con- 

 cluded they were in an early anaphase but since he considered the 

 unreduced number to be ten or twelve chromosomes the twenty or 

 more chromosomes that he saw were probably in an early meta- 



NoTE — The drawings of the chromosomes were made as carefully as possible with a camera under 

 a 1.5 mm. Zeiss apochromatic and compensation ocular 6. They were then enlarged with a drawing 

 camera about three times, corrected by comparison with the objects, and reduced by one-third in repro- 

 duction. 



