CHAP. VI. 



ANNELIDS. 



161 



segment on the right side, while that of the left side was fully 



Right 



Left (normal) 



Fig. 24. Lumbricus herculeus, having the generative organs of the right side one 

 segment higher than usual. A, external view from below. B, view of the organs 

 from above, spth, sperrnathecae ; ov, ovary; as, oesophagus ; cat, calciferous 

 glands. After Ben ham. 



formed. It is remarkable that in this case, the calciferous gland 

 of the 12th segment was absent on the right side. [I am indebted 

 to Mr Benham for an opportunity of examining this specimen.] 

 Benham, W. B., Ann. & Mag. N. H., 1891, Ser. 6, VII. p. 257, 

 PI. in. 



Another specimen presented the same variations as the fore- 

 going, both as regards the asymmetrical arrangement of the genital 

 pores and the absence of the calciferous gland : but in it there 

 were vesiculae seminales on the right side in segments 10 and 11, 

 but none in segment 9 ; and there was a spermatheca on the right 

 side in segments 8 and 9. [In the normal form the spermatheca? 

 are in segments 9 and 10, so that, in this individual in the matter 

 of the spermathecse as well as of the genital pores, structures were 

 formed in particular segments which are normally found one 

 segment lower down.] Bexham, W. B., in litt., March, 1891. 



11 



B. 



