new Genus of OligocJicvta. 83 



by an ap))roximatclj equal distance ventrally and dorsally. 

 On the vtli, vitli, and viitli segments the seta3 are consider- 

 ably larger than those whicli tbllow. A more marked dis- 

 parity, liowever, is seen in the ventral sette of segments xii. 

 and xiii. These are three or four times as large as the 

 lateral setse of tiie same segment, and as the seta3 of the 

 preceding and succeeding segments ; they give a very marked 

 character to the region of the body where they occur. In 

 their shape they are like the seta3 of the other segments of the 

 body, which have the usual Lumbricid pattern. No peculi- 

 arities distinguish the clitellur setai; the full number of sette 

 are present upon the clitellum. 



The only apertures that I could distinguish upon the body 

 of an individual cut open and mounted in glycerine were the 

 atrial pores ; and these are so little conspicuous that I only 

 observed them after I had ascertained their position by means 

 of sections. There are two pairs of atrial pores ; as in the 

 last species, they are upon two consecutive segments ; but the 

 segments are the xviith and xviiith. The pores lie just be- 

 hind and to the outside of the outermost seta of the ventral 

 couple. 



Behind the male pores is an oval median papilla upon 

 segment xix. ; the epithelium covering this papilla is com- 

 posed of very tall glandular cells with clear non-staining 

 contents. 



Internal Stfuctu7'e. 

 Above and behind the pharynx the septal glands are very 

 conspicuous ; in tiie vth, vith, and viith segments they form 

 isolated masses attached to tlie septa dividing these segments. 

 There is a well-developed gizzard in segment viii. In the 

 ixth segment the single ventral calciferous pouch is placed *. 

 It was not very well preserved in the specimens ; but its 

 structure appears to be identical with that of the pouch of 

 Gordiodrilus elegans. The septa separating segments v. /viii. 

 are very thick ; those between segments viii./xii., though 

 thinner, are yet stouter than those which follow. Tiiere are 

 two pairs of testes and two pairs of vasa deferentia corre- 

 sponding to these, which remain separate till just before their 

 external orifice. The testes and fuimels of the vasa de- 

 ferentia are as usual in segments x. and xi. The ovaries 

 are in segment xiii., and the oviducts open on to segment 

 xiv. ; there are no receptacula ovorum. 



* In another specimen, dissected since the above was written, the 

 pouches of segment ix. were paired, though ventral in position ; this 

 species is, so lav, a coimectiug-link bct\\een Gordiodrilus and Ptjymceo- 

 drilus. 



6* 



