604 FOOT AND STROBELL. [Vol. XVI. 



and acetic) shrunk the Qgg nearly one-half its diameter, and the 

 archoplasm is shrunken into compact masses that resemble rods. 

 The archoplasm of photo. 9 (chromo-acetic) forms a sharp 

 contrast to that of photo. 7. Part of it is aggregated at the 

 center of the attraction sphere, where it is stained so deeply 

 that the middle-piece is completely obliterated. 



Fertilization Cone. 



Photo. I shows the size of the cone in relation to the 

 entire Qgg (at this stage the first maturation spindle is in 

 the metaphase and at the periphery of the t%^. Photo. 2 

 is a section of such an ^gg, cut longitudinally through the 

 cone. The thinness of the section enables us to see the head 

 of the sperm within the cone, on its way to the center of the 

 egg.^ The sperm continues its course until its middle-piece is 

 near the inner aster of the first maturation spindle, slightly 

 turning and bringing its head again near the periphery, some 

 of the preparations (for example, photo. 12) producing the 

 false impression that it has entered from the latter point, 

 and the aster has formed at the apex of the head. The prog- 

 ress of the sperm towards the inner aster of the spindle 

 appears to be dependent upon the stage of development of 

 the t.g%. When the spindle has reached the anaphase, the 

 sperm aster is formed and the progress of the sperm towards 

 the center of the Q.gg then ceases, the head separates from 

 the middle-piece and contracts into a short thick rod (photos. 8, 

 16, 17, and 18). The spiral twist of the sperm shown in 

 photo. 2 is an uncommon form, but it probably does not indi- 

 cate an abnormal condition of the tgg. 



In photo. 5 we have an unmistakably pathological cone, this 

 enabling us to determine the pathological condition of the 

 rest of the cytoplasm and giving a standard of comparison 

 which may prove of service. 



Photo. 6 probably represents another example of patho- 

 logical cytoplasm, as the Qgg contains four spermatozoa, two of 

 which are shown in the section photographed. It is a question 



^ Over-printing at the apex of the cone has obliterated the sperm at that point. 



