AND OF HYBRID PIGEONS. 
61 
Fig. 34. X 
Fig. 35-36 
Fig. 37. X 
Fig. 38. X 
Fig. 40-42. 
Fig. 43-44. 
Fig. 45. X 
Fig. 46. X 
Fig. 47. X 
Fig. 48. X 
Fig. 49. X 
Fig. 50. X 
2000—A secondary spermatocyte. One of the 
four chromosomes is much smaller than 
the others. 
and 39. x 2000—Tripolar spindles in the primary 
spermatocytes of a hybrid pigeon. 
2000—Primary spermatocyte of a hybrid pigeon. 
2000—Tripolar spindle in a secondary spermato¬ 
cyte of a hybrid pigeon. The chromo¬ 
somes vary in size. 
X 2000—Spermatozoon of an infertile hybrid and 
two stages in the formation of such a 
spermatozoon. 
X 2000—Spermatids which have undergone an 
abnormal and incomplete transformation 
into spermatozoa. 
2000—Primary spermatocyte of an infertile hybrid 
showing a vacuole in the sphere. 
2000—Primary spermatocyte of an infertile hybrid 
showing a vacuole in the nucleus. 
2000—Degenerating primary spermatocyte of an 
infertile hybrid. The chromosomes have 
been formed, but no spindle has ap¬ 
peared. 
1800^—Giant cell from a tubule of an infertile 
hybrid. 
2000—Fusion of nuclei in a primary spermatocyte 
of an infertile pigeon. 
2000—Degenerating primary spermatocyte of an 
infertile hybrid. 
