292 Transactions. — Zoology. 



undulating, and bent in a U-shaped fashion. It occupies five 

 segments, 16 to 20 inclusive. The free end of the gland lies in 

 the former segment, and the closely undulating or zigzag portion 

 extends into the 20th, against the hind wall of which it bends 

 sharply on itself, and the rather wider recurved limb passes 

 forwards into the 19th, at the anterior end of which the mus- 

 cular duct commences. This is narrow and long, passing through 

 three segments to open to the exterior at the 16th segment. 

 The penial sac is also long, occupying the four segments 16 to 19 

 inclusive. 



The penial clueta (Plate XIV., fig. 7) is long, curved, with a 

 spoon-shaped pointed tip, and is without ornamentation. The 

 total length of a penial chseta is 4 mm. 



The ovaries are plainly visible in the dissected worm in the 

 12th segment. 



The single pair of spermathecpe lie in the 8th segment. Each 

 (Plate XIV., fig. 3) is a subglobular sac with a short thick duct, 

 which receives a relatively large cylindrical diverticulum which 

 is bent upon itself. 



Remarks. — The most remarkable feature about this species 

 is the apparent shifting forwards of the genital organs by one 

 segment — i.e., the genital pore, instead of being on the 17th. is 

 on the 16th segment, and each of the internal genital organs — 

 ovaries, testes, and sperm-sacs — similarly occupy the segment 

 preceding the one normal for the genus. As to the spermatheca 

 in the 8th segment, it is uncertain whether this has been 

 affected, for in R. edulis the single spermatheca «is in this seg- 

 ment, though in other species with a single pair it is in the 9th. 



The position of the male and female gonads is so constant 

 throughout the whole group of earthworms, with the exception 

 of the Moniligastridw, that this forward movement is very 

 puzzling. 



Both individuals present this same dislocation. Naturally, 

 this led me to re-examine very carefully the external and internal 

 segmentation, both with a lens of high power and, after bisection 

 and clearing, with the compound microscope, and, further, I cut 

 one individual into a series of longitudinal sections. It at once 

 occurred to me that the prostomium and peristomium might be 

 invaginated, or that an injury had .been received at this end ; 

 but the latter suggestion was negatived by the occurrence of 

 two individuals presenting precisely the same phenomenon ; and, 

 moreover, there is no sign of injury at this anterior end. The 

 prostomium is perfectly well denned ; it has the usual relations 

 to the peristomium — it is, indeed, " dovetailed " into the latter 

 segment. 



The 1st segment has no chsetse — i.e., it agrees with the usual 



