234 OLIGOCHAETA 



CLAPAREDE, NASSE, and DIEFFENBACH speak of a cavity, or, rather, several cavities 

 within the lobes of the prostate, which unite to form the common duct of the gland 

 which opens into the terminal chamber. The most detailed account of the lumina 

 is given by DIEFFENBACH (for Tubifex indeed, but the conditions do not differ in 

 Limnodrilus), and runs as follows : 



' Sie (die Kittdriise) besteht aus einzelnen langlichen Drlisenlappen, die von der 

 Miindungsstelle aus sich facherfb'rmig ausbreiten und in deren Mitte ein feiner 

 Kanal verlaufti dem die einzelnen, stark granulosen, mit grossem Kern und Kern- 

 korperchen versehenen Driisenzellen aufsitzen. Ein Theil dieser Drlisenlappen lagert 

 dem Atrium auf, die Driisengange derselben vereinigen sich mit den anderen zu 

 gemeinsamer Mundung in das Atrium.' The figure, however (fig. 5 pr.), does not 

 show these canals in by any means a convincing fashion, and there is no indication 

 of them in the figures of any authors with whose papers I am acquainted. 



VEJDOVSKY states that they develop as an outgrowth of the lining of the terminal 

 chamber, and are thus products of the epidermis. 



The distal extremity of the spermiducal gland is modified into a penis, enclosed 

 by a sheath ; the lining epithelium here is not ciliated. The penis itself is a direct 

 continuation of the spermiducal gland. The sheath has an epithelial lining, and, 

 outside of this, muscular walls, which have frequently a markedly spiral arrangement. 

 The lining epithelium of the sheath secretes a chitinous layer, which encloses the 

 penis. The development of this copulatory organ has been described by VEJDOVSKY 

 (24, p. 143), and that briefly 1 . He says 'that the cavity of the penis arises by 

 a secondary invagination ; the sheath first appears, and then, after being invaginated, 

 grows out again to form the penis. The penis and its sheath are therefore something 

 superadded to the spermiducal gland, the original orifice of which would be at a in 

 the figure.' 



This description refers to L. udekemianus ; it applies, however, to the two other 

 European Limnodrilus in every point, except that they have a double coating of 

 spiral muscles, the outer coat reaching beyond the penis-sheath for some distance 

 along the narrow terminal region of the tube. 



There are several other genera of Tubificidae in which the efferent apparatus 

 only differs in detail from Limnodrilus. In Spirosperma there is a short strongly 

 chitinous penis, and only a very slight development of muscles round the penis-sheath. 

 So, too, Lophochaeta (fig. 38), where the chitinous sheath of the penis is less strong. 

 These two genera have been described by STOLC (3). 



1 The account given by EISEN (12) is fuller, but substantially the same, apart from the curious views 

 as to the 'oviduct,' for which see p. 238. 



