78 



retractor muscle-fibres. The whole sac is situated well within 

 the segment, there being a narrow, caual-like, genital cloaca 

 (0046 mm. long) leading from the male and female openings 

 to the exterior. The male aj^erture lies just in front of the 

 female. When the sac is contracted, and the cirrus there- 

 fore everted, the former appears as a small, pyriform body 

 with rather thick, muscular walls. The everted cirrus, which 

 is about 0098 mm. long and 0015 mm. broad, projects 

 through the common genital pore for a distance of 0062 mm. 

 It possesses a very characteristic armature, represented in 

 Fig. 5 : at, and near the free end, there is a lai'ge number of 

 long, delicate, stiff, hyaline spines (0-031 mm. to 0047 mm. 

 in length), which gi'adually taper. These come to project 

 backwardly. In the figure, many are seen with their points 

 directed forwards, the cirrus evidently not being fully 

 everted. Just behind these, the tube is covered externally by 

 a great number of very small thornlike spines, biit just at the 

 base of the eversible portion, these become replaced by a 

 third kind. These last are much fewer in number, and 

 larger in size, and project more prominently than the last- 

 mentioned. They have a much wider base. 



Female genitalia,— T\\e female complex is situated at about 

 the middle of the segment, though it is generally slightly dis- 

 placed towards the pore-bearing margin. The ovaiy, when 

 mature, is a large bilobed organ, the wings being connected by a 

 short ovarian bridge which is not readily recognisable. Each 

 lobe is a rounded mass, not differentiated into egg-tubes. The 

 diameter of each is about 0'07 mm., the total breadth of the 

 organ being nearly 0-14 mm. A short oviduct passes backwards 

 from the middle of the ovary. The position of the gland in 

 relation to the testes has already been mentioned. It lies antero- 

 dorsally to the vitellarium, which is the most ventrally placed of 

 all the reproductive glands. The latter is a compact ronnd 

 organ of 0'046 mm. diameter, situated near the midline, just 

 behind and between the ovarian wings. From it the vitello-duct 

 passes foi-wards. A shell-gland was not observed, nor was the 



