new Genus of OUgochceta. 81 



the body ; each vas deferens commences with a very large 

 funnel wliicli reaches from top to bottom of tlic cavity of 

 segment xi. ; the tube arising from this passes back closely 

 adherent to the ventral parietes and opens on to the exterior 

 in the xith segment, not far behind the septum which sepa- 

 rates tliat segment from the one in front. The external 

 orifice is therefore in front of the set^ of the segment, and to 

 the outside of the ventral couples. 



There is nothing that calls for special remark in the 

 minute structure of the vasa deferentia ; they are formed of 

 the usual cubical cells, which are ciliated. At the external 

 aperture there is no glandular body connected with the vas 

 deferens, nor are there any modified setce of any kind. The 

 great length of the vasa deferentia is rather unusual ; it is 

 not often that these tubes occupy so many as ten segments, 

 though occasionally they may be even longer than in the 

 present species. Although the vasa deferentia are entirely 

 unconnected at their external orifice with any glandular 

 bodies, a pair of tubular glands open on to the exterior on 

 each side in the immediate neighbourhood of the male 

 pores. 



The tubular form of these glands, and the fact that there 

 is a pair of them on each side of the body — one in front 

 of and one behind the male pores — recalls the very charac- 

 teristic arrangement met with in the family Acanthodrilldte, 

 and hitherto only found in that family *. But although 

 there is this general similarity, there is also an important 

 difference, namely that the atria, as I may term them, open 

 on to two consecutive segments in Gordiodrilus tenuis. These 

 segments are xx. and xxi. 



In the Acanthodrilidffi the atria are, as I myself was the 

 first to point out, quite independent of the vasa deferentia ; 

 but they open nearly invariably f on to the xviith and xixth 

 segments. 



The atria extend through several segments ; they are, as 

 in Acanthodrilus, bent upon themselves once or twice. The 

 minute structure of the atria is also of interest. As in 

 Acanthodrilus and in other genera in which there are tubular 

 atria, the glands consist of a glandular and a muscular 

 part. The muscular part of the atrium is rather short. The 



* Bourne's Pcrichceta Stvarti, which appears to show something of 

 the same kind, requires re-investigation. 



t Perrier (Ts'ouv. Arch. d. Mus. t. viii.) has described the atrial pores 

 of both Acanthodrilus obtvsus and A. verticiUatus as being upon two 

 consecutive segments ; the xixth and xxth in one case the xviith and 

 xviiith in the other. 



Ann. & Mag. N. Hist. Ser. 6. Vol x, 6 



