No. 2.] THE SPERMATOGENESIS OF LUMBRICUS. 277 



III. Phenomena of Reduction. 



As previously stated, my results regarding the reducing 

 divisions are not wholly satisfactory, owing to the smallness of 

 the cells and to their lack of consecutive arrangement in the 

 testis and vesicles, 



A. Spermatogonia. 



The spermatogonia are represented in the testes by the 

 multinucleate cells (Fig. 2). The nuclei are small, yet larger 

 than those of the epithelial cells from which they arose, and as a 

 rule have no nucleoli (Figs. 2 and 3). The chromatin is distinct 

 but not abundant, nor is there any characteristic form. In 

 the cytoplasm by the side of each nucleus is a large and rather 

 indefinite faintly staining body (see Section V). As the nuclei 

 prepare for division, the Kndicel or spirem stage is less con- 

 spicuous than in the later sperm cells, its filaments being fine 

 and indefinite. In full karyokinesis neither asters nor astral 

 rays can be seen. Picric acid preparations show small dots, 

 the centrosomes, or archoplasm masses at the poles, and spindle 

 fibres can be traced directly into the chromosomes (Fig. 8) ; 

 the nuclear plate contains thirty-two small and apparently 

 spherical chromosomes (Figs. 7 and 8). 



B. Spermatocytes of the First Order. 



Spermatocytes of the first order cannot be distinguished by 

 their external appearance. The nuclei have migrated, how- 

 ever, to the periphery of the cell (Fig. 3). I am unable to 

 assert whether karyokinetic divisions of these nuclei intervene 

 between the divisions occurring in the testis and the migration 

 of the nuclei to the periphery of the cells in the seminal 

 vesicles. Such, however, is probably not the case, because of 

 the scarcity of karyokinetic figures in the testis, and because 

 of the average number of nuclei in the multinucleate cell. It 

 seems probable, therefore, that the final division in the testis 

 gives rise to spermatocytes of the first order. Each of these 



