EARTHWORM. 317 



m. Infundibular ciliated mouth of oviduct. 



n. Oviduct in the posterior of the two somites to which it is related. 

 As it passes through the dissepiment separating the thirteenth from 

 the fourteenth somite, the oviduct has a saccular dilatation a 

 receptaculum ovorum ordinarily found to contain ova, appended to 

 it. It then passes outwards in relation with the dissepiment, and 

 opens externally to the internal row of setae. It is crossed just 

 before its termination by nephridium, c 5, which is related to the 

 same somites. 



Note. The prostomium is numbered in this plate as the first somite. It 

 appears, however, to be not a somite but an outgrowth of the somite numbered ii 

 here. See p. 197, ante. The receptaculum ovorum is said, in Bergh's account, 

 Z. A. ix. 1886, pp. 232-3, to belong to a septum that which separates somite 

 twelve from somite thirteen. It does so belong, provided the prostomium is not 

 reckoned as a somite. But if it is reckoned as a somite, the septum in question 

 is that which separates somite thirteen from somite fourteen. The usual mode of 

 reckoning the somites followed in this plate has also been followed in the de- 

 scription of the preparations of the Earthworm, pp. 196-212, but it is probably 

 wrong. 



