256 FRANK E. BEDDAED. 



structures. The external orifice does not appear to be pro- 

 vided with the cup-like sphincter found in Pontoscolex and 

 Onychochseta. In the posterior segments of the body are 

 the " pyriform vesicles" so characteristic of Pontoscolex ; 

 they seem to open, as in Pontoscolex/ into the duct of 

 the nephridium, and not separately on to the exterior. As 

 in many Geoscolicidse, the anterior pair of nephridia are 

 larger than those which follow : these enlarged organs cor- 

 respond to the ^' glandes a raucosite" of Pontoscolex; but 

 in that worm the glands do not open into the buccal cavity, 

 although they may be sometimes temporarily retracted, so as 

 to open into it by the introversion of the anterior segments. 

 In Trichochseta, on the other hand, there is no doubt about 

 the fact that these first nephridia do open into the buccal 

 cavity. The only other species among the Geoscolicidae in 

 which these nephridia open in the same way into the ali- 

 mentary canal is the recently described Rhinodrilus 

 ecuadoriensis.^ 



One of the most noteworthy characters of this worm is the 

 form of the sperm-sacs (see fig. 4) ; in many Geoscolicidae 

 the sperm-sacs are of great length, and present only to the 

 number of a single pair. In Geoscolex forguesi the ex- 

 treme is reached, the sperm-sacs occupying forty-six segments; 

 but even those dimensions are exceeded by the Eudrilid 

 Polytoreutus magileusis described in the present paper. 

 In Trichochseta the sacs occupy about fifteen or twenty 

 segments ; they lie on each side of the gut, and appear on a 

 dissection of the worm as two thin white threads which have 

 not so great a diameter as the nerve-cord. Proximally — that 

 is, near to their origin from the septa — the two sacs are narrow 

 with even contours ; further back tiiey present the remarkable 

 appearance shown in fig. 3. The sac is provided with a double 

 series of diverticula, which vary in length from mere uipple- 



* F. E. Beddard, " Observations on the Structural Characters of Certain 

 New or Little-known Earthworms," ' Proc. Roy. Soc. Edin.,' vol.xiv, p. 100. 



^ "An Earthworm from Ecuador," 'Aim. Mag. Nat. Hist.,' scr. 6, vol. 

 ix, p. 240. 



