268 MICHAEL F. GUYER. 



PLATE VII. 



All drawings except 181, 199 and 200 were made from smears. Figs. 176, 180, 

 182, 183. and 186 are from the Langshan, Figs. 175, 177-179, 181, 184, 185, 187 

 and 188 are from the Rhode Island Red, Figs. 189, 190 from the Guinea and the 

 remaining figures from the Plymouth Rock Fowl. 



FIGS. 175-183. Characteristic metaphases of secondary spermatocytes with 

 four chromosomes. The double nature of the individual chromosomes is shown 

 in 180. 



FIGS. 184, 185. Secondary spermatocytes showing five chromosomes. Two 

 of the chromosomes are small and are probably comparable to one of the larger 

 ones, having failed to unite. 



FIGS. 186-188. Anaphases in secondary spermatocytes showing four chromo- 

 somes at each pole. 



FIGS. 189-191. Secondary spermatocytes from the guinea fowl showing four 

 chromosomes. 



FIG. 192. Probably a second (anomalous) division in a secondary spermatocyte. 

 Both spindle and chromosomes are reduced in size. 



FIG. 193. A first and a second division of four-chromosomed secondary 

 spermatocytes which lay side by side in a smear. The first is regarded as normal, 

 the second is probably anomalous. 



FIGS. 194-197. Various phases in the division of the smaller sized (probably 

 anomalous) four-chromosomed cells. 



FIG. 198. Anomalous division figure showing still further reduction in number 

 and size of chromosomes than that shown in 197. 



FIG. 199. Nucleus of resting spermatid. 



FIG. 200. Typical appearance of normally transforming spermatids. 



FIG. 201. Conditions comparable to those shown in Fig. 193. 



FIG. 202. A stage similar to that shown in 195. 



FIG. 203. Normally transforming spermatids. 



FIG. 204. Spermatids which are probably abnormal or degenerating. 



