682 OLIGOCHAETA 



the oesophagus extends to the ■ twentieth segment ; in the twenty-first begins the 

 intestine, which has a typhlosole ; this typhlosole gets to be, in segment xxviii, of 

 enormous size, almost filling up the lumen of the intestine ; it is figured by Rosa 

 as being much folded. The first part of the intestine occupying segments xxi-xxviii 

 has faintly marked lateral caeca ; after the last-named segment, these caeca disappear 

 and the intestine presents a normal appearance. It is in the posterior section of the 

 intestine that the typhlosole acquires its full development. Concerning the circulatory 

 system, Rosa gives but few details ; a subnervian vessel exists ; in the anterior region 

 of the body the dorsal vessel is double, a condition common among earthworms. 

 There appears to be no supra-intestinal vessel ; at least, no mention of one is made. 

 The reproductive organs present no special features of interest ; the usual two 

 pairs of testes lie attached to the anterior septum of their segments in segments x 

 and xi ; opposite to them are the funnels of the sperm-ducts ; the two ducts of each 

 side unite in the twenty-first segment and pass on to the external pore, which is, as 

 already stated, upon segment xv/xvi. The sperm-sacs are racemose organs and lie in 

 segments xi and xii, being confined to these segments and not extending beyond them 

 as is so often the case with worms belonging to this family ; as in Microchaeta, and 

 in certain other genera of Geoscolicidae, there are egg-sacs — one pair in segment xiv. 

 The ovaries and the oviducts are perfectly normal. 



Hormogaster redii, Rosa. 

 H. redii, Rosa, Mem. R. Ace. Torino (2), xxxix, 1889, p. 49. 



Definition. Length, 160 mm.; number of segments, 300-380. Colour earthy brown, 

 jleshy below. l^ejphriAiojaores in front of second seta, commencing with the fifth segment. 

 Hob. — Italy. 



Genus Siphonogasteb, Levinsen. 



DuFmiTioiT. Setae paired, ornamented. Clitellum?; on eighteenth segment a 



pair of long penial processes, provided with modifled setae, in the middle of 



which open the sperm-ducts. Oesophagus without gizzard or calciferous glands. 



Spermathecae absent. 



This genus was first made known by Levinsen, who described (1) a single 



species from the banks of the Nile from material in a poor state of preservation. 



Two species from the shores of Victoria Nyanza were subsequently investigated by 



