22 Mindeskrift for J, Steenstrup. XXV. 



In the female the vulva is situated rather near the tail. In a female of 2^/2 ctm. 

 having reached its maturity, the vulva is placed 2,5 mm, from the tip of the tail; 

 in a female of about 6 ctm, the distance from the vulva to the end of the tail is 

 7 mm. In a female of 3,6 ctm, the vulva is situated almost 4 mm. from the tip 

 of the tail, It is very difficult to obtain absolutely exact measurements ; in the first place 

 preparations of females tolerably extended are found but very seldom; as a rule they 

 will be considerably curved, bending from one side to the other and — which is 

 still worse — in several cases twisted. Secondly, even exact measurements may not 

 be in keeping with the facts on account of the great power of contraction met with 

 in this species, as the measurements will vary according to the momentary state of con- 

 traction. Generally, however, the distance from the vulva to the tail may vary between 

 ^/s and ^/lo of the whole length of the animal. 



It is no easy task to fix the place of the vulva; the two uteri are extending 

 far forwards and backwards in the body and often — especially in bigger specimens — 

 are fiUed with eggs to such a degree that the whole cavity of the worm may 

 be taken up by these organs, the intestinal canal and the ovaries being forced aside; 

 as the vulva is but little prominent itself it often may take a long time to find it. 



Flg. 1. 



The interior female organs as already hinted, are double, The vagina extends 

 from the vulva a little way in the direction of the head, af ter which the two uteri 

 are branching ofT, one of them in the cephalic the other in the caudal direction, 



Near the limit between oesophagus and the Chylus-intestine, and somewhat post- 

 erior to the vulva the two uteri pass into resp. the anterior and posterior Recepta- 

 culum seminis which by a short curved oviduct communicate with the corresponding 

 ovary. It seems to be the rule that the end of the front ovary is pointing towards 

 the tail, .the end of the hindmost ovary towards the head. The ovaries are strongly 

 bent and apparently rather gratuitously; on f urther examination the windings appear 

 to be rather typical; deviations may be found as was the case with the testes in the 

 male — but they are not the rule. The windings always correspond to the 

 longitudinal axis of the animal, nearly constantly ventro-dorsally bent or vice versa, 

 The course of the ovary is either cephalic or caudalic. After a little while it suddenly 

 turns, running now parallel to its first course but taking a converse direction. After 

 some time it turns again and now keeps this course at a distance twice the length of 

 the first one; it then turns again and runs towards the first point of curving where 

 once more it turns, The course of the ovary thus describes a line corresponding to 

 the longitudinal axis of the animal and presents itself as follows: (Text fig, 1), 



