125 



occupying a part of somite 12. This reservoir is roughly triangular 

 in shape, with the base and larger part of the triangle in the left half 

 of the somite and the apex extending over into the right half. 



Seminal Funnels. 



The usual two pairs of seminal funnels are found in somites 10 

 and 11. On the left side there is an extra, unusually large funnel, 

 lying in the extra posterior sperm reservoir of that side (sf.). This 

 funnel is of such size as to extend across the middle line into the 

 right side, a part of it lying behind the testis on that side. In every 

 feature except size this funnel was normal. 



Seminal Ducts. 



The vasa efferentia and vas deferens of the right side are entirely 

 normal. On the left side the vas deferens (vd.) opens to the out- 

 side in somite 16 instead of 15. There are on this side three vasa 

 efferentia connecting with the three seminal funnels. The two anterior 

 join in somite 12 and the third (ve.) joins the common duct in 

 somite 13. All these are normal in appearance. 



3. Female Reproductive Organs. 



Ovaries. 



There are two pairs of well developed ovaries, one pair as usual 

 in somite 13 and another supernumerary pair in somite 14 (ov.). 

 These have their usual points of attachment to the septa. 



Oviducts. 

 On the right side there is a normal oviduct opening to the out- 

 side in somite 14 with its funnel in the next anterior somite. On 

 the left side there is an oviduct (od.) situated one somite posterior to 

 that on the right side. 



4. Conclusions. 



There are certain correlations present in this case of variation 

 which I think may throw some light on the relation of normal and 

 teratogenetic development. 



In the first place the genital glands themselves (ovaries and testes) 

 occur in pairs. That is wherever the block of mesoblast on one side 

 of the middle line gave use to either an ovary or a testis, the cor- 

 responding block on the opposite side gave rise to a similar organ. 

 This relation holds of course normally in the earthworm and also in 

 nearly all cases of variations in the reproductive apparatus which have 

 been recorded for this group. A case in point is that described by 



