486 H. F. MOORE. [Vol. X. 



with the post-setal glands in the neighboring somites, and are, 

 perhaps, homologous with the capsulogenous glands of Peri- 

 chaeta and other genera (3). 



In Bimastos the muscular coat of the prostate is much weaker 

 than in Moniligaster, and is scattered irregularly through the 

 glandular mass, instead of forming a zone just without the 

 columnar lining cells, as in M. Barwelli (2), or deeper in the 

 walls, as in M. indicus (5). 



The gland cells are also less distinctly arranged in bundles 

 than in the forms mentioned, and in this respect are more like 

 those in the glandular portion of the prostate of Deinodrilus 

 and its allies. The swollen heads of the cells, however, show 

 a tendency towards bunching. 



Benham has furnished us with a reasonable explanation of 

 the much-discussed relations existing between the parts just 

 described and the atria and prostates of Tubifex. According 

 to his view, the columnar epithelium and the scattered muscle 

 fibres are the much-reduced remains of the atrial wall, whilst 

 the gland cells are referrible to the cement glands. 



As I shall show, the cement glands of Tubifex and the chitin- 

 producing cells of Bimastos perform the same function in the 

 economy of reproduction. 



From the shape of the atrial cavity and the character of the 

 cell products I was early led to credit this organ with the fabri- 

 cation of the spermatophores, and it was with considerable 

 satisfaction that I afterwards found spermatophores in the 

 course of manufacture within the cavity. In many instances 

 it was possible, in sections, to follow the chitin filaments from 

 the mouths of the cells, or even from some distance within the 

 cells, to the walls of the spermatophore. From their position 

 in the atrium it would appear that the spermatophores are ex- 

 truded "head" first. 



Lankester (8) and others have long ago shown that the sper- 

 matophores, or sperm ropes, of Tubifex are formed by the 

 secretion of the cement glands poured into the atrium as a 

 matrix. It is generally claimed, as stated by Vejdovsky (11), 

 that in the Lumbricidae, which have no atria, the spermato- 

 phores are secreted by the spermathecae, that is, by the female 



