386 The Spermatogenesis of Bufo Lentiginosus 
EXPLANATION OF PLATE III. 
Fic. 47. Metakinesis of the first maturation division. Chromosomes of 
different types on the same spindle. 
Fig. 48. Same stage as the preceding, showing the great difference in the 
size of the chromosomes. 
Fic. 49. Early anaphase of the first maturation mitosis. 
Fies. 50-52. Anaphase of the first maturation mitosis. 
Fic. 538. Massing of the chromosomes at the spindle poles in the late 
anaphase of the first maturation mitosis. 
Fic. 54. Secondary spermatocyte. Division of the centrosome preparatory 
to the formation of the second maturation spindle. 
Fic. 55. Metaphase of the second maturation mitosis, showing an amor- 
phous mass of chromatin at the equator of the spindle. 
Fic. 56. Equatorial plate of the second maturation spindle. Only nine of 
the twelve chromosomes are shown. 
Fic. 57. Early anaphase of the second maturation mitosis. 
Fig. 58. Very young spermatid showing the single centrosome and the 
acroblast. 
Fic. 59. Young spermatid. The centrosome has divided and the surround- 
ing vesicle has come in contact with the nuclear membrane to form the 
middle-piece. 
Fics. 60-70. Stages in the development of the spermatid into the sperma- 
tozoon. 
Fic. 71. Mature spermatozoon stained lightly with iron-hematoxylin. 
