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Transactions of the Societ]/. 



Their walls are of moderate thickness, and have a layer of circular 

 muscles which is strengthened internally by annular thickenings at 



Fig. 11. — Mermis myrinecophila. Lateral view of vagina and its con- 

 nexions in an adult female. The arrow points towards the head, 

 o., ovejector ; u., uterus ; v., vulva ; ve., vestibule. 



regular intervals. Each uterus passes suddenly into a narrower 

 duct, about 0'3 mm. long and with thick muscular walls. After 

 forming a half-turn of a spiral, this duct in turn opens into a very 



O'i 'mnt. 



Fig. 12. — Mermis myrinecophila. Three adjacent ova as seen in position 

 when laid in the cast-off cuticle. The solid black circle represents 

 the actual shell of the egg ; the clear space outside it the hyaline 

 covering. 



wide tube, about 5 mm. long and filled with eggs. This may be 

 regarded as the oviduct. Its walls are scantily provided with 

 muscles. It passes gradually into the ovary, which runs almost 



