SPECIES OF THE GENUS AULODRILUS. 961 



about ^ mm. distance behind it. It is filled with a large mass of 

 yolk granules, and also contains a number of ova at various stages 

 of maturity. 



The female funnel is very small. Its posterior wall (the one 

 nearer the septum behind) is represented by a patch of columnar 

 epithelial cells of about 25 //. by 5 /i size lying on the anterior face 

 of septum 7/8 near the ventral parietes, below the point where this 

 septum is bulged backwards to form the ovisac. The anterior 

 wall is, however, smaller and somewhat less conspicuous in sections. 

 The epithelial cells of the funnel contain oval nuclei of 2*5 m 

 diameter. 



The oviduct is extremely short, about 40 ju in length ; it runs 

 backwards and downwards somewhat obliquely to pass through 

 the body-wall, through which it runs as a narrow irregular 

 channel of about 25 p. length and 4/i breadth. The female 

 opening is wider at the inner margin of the epidermis and 

 narrower at the outer. 



The spermathecse occupy segment 6 ; they lie freely for the 

 greater part of their length in the central chamber of the body- 

 cavity and are attached to the partition wall at the ventro-lateral 

 corners as they pass downwards to their openings, which lie about 

 the middle of the segment, much in front of the ventral seta3. 

 They are of considerable length and bent, so that each consists of 

 two parts, a vertically elongated terminal portion — the duct, and 

 an inner sac-like portion — the ampulla. The duct is not sharply 

 marked off from the ampulla, but gradually passes into it. The 

 ampulla is simple, and in the later stages of maturity quite large. 

 The length of the spermatheca is 234-305 fi. The duct is circular 

 in transverse section, about 88-133 /x in length and 48"5 /a in 

 diameter; in one case it measured 175 /x in length. Its wall is 

 17-20 /x thick, and is composed of an inner lining of columnar 

 epithelial cells, surrounded by a coat of muscle fibres, with a thin 

 layer of peritoneum outside. The epithelium is composed of a 

 single layer of tall columnar cells of 10-14 yu height and 3 /x 

 diameter, containing oval or somewhat elongated nuclei near the 

 periphery, which lie with their long axis parallel to the height of 

 the cells. The muscular sheath of 2 ^ thickness consists of an 

 inner thin layer of circular muscle fibres and an outer thicker one 

 of longitudinal muscle fibres. The peritoneum as usual consists 

 of a layer of thin flattened cells with prominent nuclei. Near 

 the opening the wall of the duct is less thick than in the upper 

 part ; the epithelial cells here are less tall, being neai-ly of the 

 same height and form as those of the epidermal cells with which 

 they are continuous ; here the muscular coat is also thinner and 

 is continued into that of the body-wall. The nuclei of the epithelial 

 cells in the terminal part are not elongated, but somewhat 

 rounded, and lie about the middle of the cell. The ampulla is 

 much larger than the duct; its length varies considerably — in 

 three specimens it was 145, 185, and 295 fx ; the maximum breadth 

 was about 120/x. Its wall is much thinner than that of the duct. 



