ON THE ORIGIN OF THE SPERM-BLASTOPHORE 

 OF SOME AQUATIC OLIGOCHAETA. 



SHINKISHI HATAI. 



THE first investigator to discuss the -origin of the sperm- 

 blastophore in Oligochaeta was Bloomfield. 1 His work was 

 done mostly on living material, although he supplemented it to 

 some extent by preparations mounted in glycerine. He studied 

 the external features only. Later, Calkins 2 published a de- 

 tailed account on the same subject, his views being opposed 

 to those of Bloomfield. Both of these writers made their ob- 

 servations upon Lumbricus terricolae. A more complete state- 

 ment of their respective views will be given on a later page. 



In the Limicolae the origin of the sperm-blastophore has 

 not yet been studied, although some work on the structure of 

 Limnodrilus Gotoi 3 and Vermiculus limosus 4 of this group 

 has been published recently. These species are common in 

 Japan. The material used in the present study was fixed in 

 Perenyi's fluid and corrosive sublimate. The stains used were 

 Kleinenberg's haematoxylin, Rawitz's haematoxylin, and borax 

 carmine. 



The present article deals only with the formation of the 

 sperm-blastophore. The various stages in its development 

 may be described advantageously in the following order : 



i. Spermatogonia. A section of the testis (Fig. i) shows 

 three stages in the maturation of the spermatogonia, namely : 

 (a) The cells at and near the proximal end of the testis are 



1 Bloomfield, E., " On the Development of the Spermatozoa, i. Lumbricus," 

 Quart. Journ. Micr. Set. Vol. xx. 1880. 



2 Calkins, G. N., " The Spermatogenesis of Lumbricus," Journ. of Morph. 

 Vol. xi. 1895. 



3 Hatai, S., "On Limnodrilus Gotoi (n. sp.)," Annotationes Zoologicaejaponesis. 

 Vol. iii, Part i, 1899. 



4 Hatai, S., " On Vermiculus limosus," Annotationes Zoologicae Japontsis. 

 Vol. ii, Part iv, 1896. 



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