end. Vaginal glands are present. The vagina is short 

 and leads back into the large common uterine tube. The 

 proximal part of the uterus may be considerably distended 

 (fig. 1) by the mass of contained embryos. The main tube 

 is a wide organ (0*07 mm. diameter) passing back for about 

 2*2 mm. where it bifurcates, each half being crowded with 

 embryos. In some of the fragments they contain eggs, 

 usually with a vermiform embryo within each, whilst in 

 other fragments parts of the paired ovaries may be seen. 



In our preliminary communication we stated that the 

 worms were ovoviviparous and viviparous, but as a result 

 of having examined more material we think that F. gibsoni 

 normally is viviparous. As mentioned above, the uterus 

 is crowded in its lower parts with free embryos, whilst 

 further back eggs containing worm-embryos are mingled 

 with the free embryos. We have seen the young worms 

 escaping through the vulva. In two instances, however, 

 we saw embryo-containing eggs in the vaginal region. 



If a fresh "worm-nest" be cut across and a smear 1 be 

 made from the cut surface, eggs and embryos in various 

 stages of development will be met with. Apparently the 

 ova after fertilisation develop very rapidly, the embryos 

 being stored up in great numbers until a favourable oppor- 

 tunity for their liberation arises. 



The fully developed embryo may be seen closely coiled 

 up in its thin rounded or elliptical shell of about 0*03 by 

 0*045mm.dimensions(fig.3). Later, the little worm becomes 

 free in the uterine cavity, the shell perhaps becoming 

 absorbed as we have not noticed any empty egg-cases. 



Its length now varies from 0*22 to 0*27 mm., being usually 

 about 0'25 mm., the breadth being 0*003 to 0*004 mm. 

 The anterior end is blunt and almost straight, the tail 



1 We have found Gietnsa's stain to give the most satisfactory results. 



