MEGASCOLECIDAE 277 



(Fig. 3 a). The remaining internal characters are essentially as described for the type 

 specimens. 



Abnormal specimens. Two abnormal specimens were encountered in the collections of 

 M. georgianns. Since such abnormalities are of frequent occurrence in Oligochaetes and 

 have been made the subject of special study by various authors (the literature is 

 reviewed by Stephenson^), it is only desirable here to indicate the main external features 

 of these specimens. 



In a clitellate specimen from Larsen Harbour, 6. i. 27, the left side of the animal is 

 entirely normal but the right shows several abnormalities. Segment 9 is divided by a 

 furrow on the right side, and there are three spermathecal pores beginning at inter- 

 segment 8/9. The right female pore is on segment 15 instead of 14. Segment 18 is also 

 divided by a furrow on the right side, and there are three prostatic pores on segments 

 18, 20 and 21. There is no seminal groove in connection with the first of these; from the 

 second a groove extends half a segment forward and from the third half a segment 

 backwards. No male pore or pores can be seen externally on the right side. The 

 clitellum is also peculiar on the right side, extending over segments 14-17 continuously, 

 absent on 18, and recurring again on segment 19. 



In a poorly preserved specimen from Wilson Harbour, 19. i. 27, an even more ab- 

 normal condition is found. Segments 1-3 appear to be normal, segments 4-7 are so 

 subdivided by spiral furrows as to be quite confused. There are three pairs of sperma- 

 thecal pores immediately behind this region. If the first spermathecal pore is assumed 

 to be at intersegment 7/8, then the next two are at intersegments 9/10 and lo/ii respec- 

 tively. The clitellum is apparently normally situated in reference to this region, on 

 segments 14-16, but it is poorly defined and owing to bad preservation the female pores 

 are not visible. The prostatic pores are situated very far back and are abnormally 

 arranged. On segment 26 (on the assumption previously indicated) there is a pair of 

 prostatic pores ; on 27 a second prostatic pore on the right and a male pore on the left ; 

 on 28 a prostatic pore on the left and a male pore on the right ; on 29 what appears to be 

 an additional male pore on the left and a third prostatic pore on the right; on 30 

 apparently a small pair of prostatic pores. Either serial sections or careful dissection 

 would be necessary to confirm these statements, but owing to the poor state of preserva- 

 tion no such examination has been attempted. 



Observations. This species is exceedingly close both to M. faldandicus and to M. 

 aqiianimdiilcium from the Falkland Islands. The differences separating these species 

 are discussed under M. faldandicus. 



f. reductus, nov. 



In wet moss 200 ft. above Upper Lake, St. 122, South Georgia, 14. xii. 26; one fully, one partly 

 clitellate and one non-clitellate semi-fnature specimen {type and para types). 



These specimens only differ from the typical form in the absence of the posterior pair 

 of prostates and penial setae ; they are in essential agreement with f. georgianiis in all 



1 Stephenson, J., The Oligochaeta, Oxford, 1931. 



