• THE ANATOMY. OVIDUCTS 101 



segment; this pore has been figured by d'Udekem (2), and by Stolc (1), whose 

 account, though establishing that of d'Udekem, is more recent, and being the result 

 of more refined methods of investigation is important if only as a confirmation 

 of the earlier description. 



Among the Naidomorpha similar pores appear to exist. It is among the 

 Enchytraeidae that we first meet with indications at least of special tubes which 

 conduct the ova to the exterior ; the structure of the oviducts in this group of the 

 Oligochaeta is such as to suggest a degenerate condition. Buchholz controverted 

 the opinion of d'Udekem that the sperm-ducts served as the conduits for the ova 

 also, and suggested that there might be simple pores in the skin through which the 

 ova made their way to the exterior ; such pores, however, were not found, though 

 Buchholz believed that they were probably small, owing to the ease with which 

 the ova could alter their size. Clapakede (3) described in Enchytraeus vermicularis 

 a pair of orifices upon the twelfth segment (this position is erroneous) ; these orifices 

 were figured (PL IT. fig. 8o) by Clapakede as existing on the same segment as that 

 which bears the male pores ; this error is due to the fact that CLAPARiiDE was not 

 aware that the setae were absent on the segment which bears the male pores ; hence 

 he thought that the pair of setae behind the male pores belonged to that segment ; 

 Vejdovskt (3) verified the existence of these pores by treating the living worm 

 with a drop or two of Osmic acid which caused the pores in question to open widely 

 and occasionally eggs were seen to pass out of them. They were, however, regarded 

 as mere pores by Vejdovsky and by Michaelsen (4) in his account of Enchytraeus 

 moebii. Michaelsen, however, spoke of ' trichterfdrmige Einsenkungen des Dissepi- 

 ments 12/13 in das 13. segment.' And in his many subsequent papers upon this 

 group of Oligochaeta he used the same expression. I have given (49) a figure 

 of the oviducts of Pachydrilus ; they appear to consist of a few pear-shaped 

 cells, not ciliated, which fringe the orifices. The degeneration of these structures 

 is curiously paralleled by the degeneration of the spermathecal duct in Nemerto- 

 drilus, where an orifice only has been left fringed with very similar cells on its 

 coelomic side. 



The oviducts in the Tubificidae and Lumbriculidae are very similar to each other. 

 The curious belief that in the former the oviducts form a sheath to the spermiducal 

 gland I deal with later. The oviducts in this family, so far as they are known, are, 

 as in the Lumbriculidae, short tubes which open into the coelom by a wide funnel. 

 It is in the earthworms that the oviducts form long tubes, but not everywhere. 

 Generally, indeed, the large funnel is followed by a very short tube leading to the 

 exterior. In such cases, e.g. Lumbricus, Perichaeta, the oviduct is very little more 



