102 S. GOTO. 



much like the albuminous substance contained in the egg-capsules of 

 the earthworm and other animals when coagulated ; and the wall was 

 completely shrunken, apparently owing to the great secretory activity 

 which produced the coagulum. I have not, however, been able to 

 study the minute structure of the gland in this genus owing to 

 scantiness of the material and its imperfect preservation ; and I must 

 therefore content myself with the above meagre account. What von 

 Linstow'^ calls the " Samenblase" in Phylline Hendorffii and P. J. v. 

 Beneden^^ the " vesicule seminale" situated outside the penis in E. 

 Hippoglossi, is undoubtedly the prostate gland. I also think that 

 what St.-Remy'^ calls the "vesicule prostatiquc accessoire" is nothing 

 else than a portion of the prostate gland which seems, in Phyllonella 

 solece according to that writer's account, to consist of numerous 

 lobes. 



In Tristomum the prostate gland is much developed and has been 

 already observed by my predecessors. It consists of numerous unicell- 

 ular glands with exceedingly long necks, which in some species, e. g., 

 Tiist. foliaceum, are arranged distinctly in two separate groups 

 (PL XXV, fig. 9). The cells themselves are scattered without any 

 order through the mesenchyma of the median and lateral portions of 

 the body around the foremost part of the vas deferens (PI. XXII, 

 fig. 1). They present somewhat diflferent aspects according to the dif- 

 ferent states of their secretory activity. They are either polygonal or 

 spherical, but are of very different sizes ; the smaller ones stain 

 deeply and their protoplasm is finely granular, while the larger ones 

 have a more coarsely granular and more weakly staining protoplasm. 

 The nucleus is always very distinct ; it is vesicular, and contains 



1). Ton Linstow — Beifcrag zur Anatomie von Phylline HendorSii. Archiv f. mik. Ana- 

 tomie, Bd. 33, 1889, p. 171. 



2). P. J. T. Beneden — Memoire sur les vers intestinaux. p. 29 & PI. Ill, fig. 1. 

 3). St.-Eemy — Etude de I'appareil genital ohez les TriBtomiens, p. 17. 



