DESCRIPTIONS OF GENERA AND SPECIES 575 



sperm- duct, just where it leaves the funnel, is dilated to form a wide sac, spherical in 

 form ; shortly after this description, Rosa found the same dilation of the proximal 

 pai-t of the sperm-duct in Teleudrilus ; it also occurs in Hyperiodrilus, Heliodrilus, 

 and in a few others ; in the latter genera, as well as in Teleudrilus, the sperm-duct 

 perforates the septum, near to which it opens into the body-cavity, twice ; the funnel, 

 that is to say, is directed towards the external orifice of the sperm-duct, and away 

 from the testes: The two sperm-ducts, if there are two pairs, never join until just 

 at their opening into the spermiducal gland ; in Evdrilus these ducts have a moderately 

 thick muscular coat. The spermiducal gland is always present, and generally has 

 a tolerably thick muscular covering, which is very well marked, for example, in 

 Eudrilus. It is a very characteristic feature of this family that the sperm-ducts 

 open into the gland itself, and not into its muscular duct, as is the case, for example, 

 with the Perichaetidae and Cryptodrilidae ; in no other family of earthworms^ except 

 Moniligaster and certain Geoscolicidae, has this state of affairs been found. I have 

 commented upon it elsewhere (p. 105), in relation to the homology of the spermiducal 

 glands thi'oughout the entire group of Oligochaeta. The spermiducal glands commonly 

 open on to the exterior through a terminal sac, which is not at all glandular, and 

 is clearly, in many cases at any rate, eversible, forming thus a penis. Only in one 

 species is the gland single ; in all others there are two, which, however, open in 

 the majority by a single pore ; in Eudriloides durhanensis there is a single and 

 medianly situate spermiducal gland; in this case, however, the cavity of the gland 

 is divided by a longitudinal septum. 



Peculiar to the Eudrilidae, and apparently confined to the genera Eudriloides and 

 Notykus are certain glands connected with the spermathecal sac. These occur in 

 Eudriloides cotterilli and E. hrunneus, and in N. emini. Their minute structure 

 has been described in Eudriloides only. 



The ovaries in aU Eudrilidae are placed in the thirteenth segment ; they invariably 

 lie attached .to the anterior wall of that segment ; there is, in fact, nothing in any 

 way difierent from other earthworms in their position. It is, however, the case that 

 the ovaries are not always recognizable in the sexually mature worm. Hence the 

 exact position of these gonads is not quite certain in a few forms. In Eudrilus the 

 ovaries can be readily found in the adult worm, but in Lihyodrilus this is not so ; 

 there is no trace, or possibly only the merest trace, of ovaries in the mature worm ; 

 in the immature worm the ovaries are visible in the usual position; so, too, with 

 Polytoreutus violaceus, and perhaps the other species of this genus ; the ovaries have 

 been with considerable uncertainty identified with masses of quite undifferentiated 

 cells lying in the spermathecal sac. The inconspicuous character of the ovaries in 



