I9I4-] J- Stephenson : Littoral Oligochaeta. 259 



in Rosa's examples; though he aud I describe the area surround- 

 ing the male pores in different ways, there appears to be an 

 essential similarity between the two accounts. 



I have also compared Beddard's account of P. laccadivensis 

 (3). This latter is a larger worm, and the spermathecal aper- 

 tures are situated, in some but not all individuals, near the 

 extremities of long dumbbell-shaped cutaneous thickenings in | 

 andf; but the male area (illustrated not in the original paper, 

 but in 4) resembles very much that of P. ephippiger. Since 

 P. ephippiger is a variable species (compare the data as to size, 

 papillae, first nephridia, characters and length of spermatheca and 

 diverticulum given above, from a limited number of specimens), 

 and P. laccadivensis is so also, at least in the matter of cutaneous 

 thickenings or papillae, I believe that the two species should be 

 united, 



Michaelsen has recently united P. insularis (Rosa) with his 

 own species P. arenae and Beddard's P. bermudensis (compare 5, 

 and the lists of Indian species in 6 and 7). I can see no essential 

 difference between the descriptions of P. ephippiger and P. arenae, 

 except that the setae are ornamented in P. arenae, not in P. ephip- 

 piger ; and when the revision of the genus is next undertaken it 

 will be necessary, I believe, to consider whether this is sufficient 

 to distinguish them; since Beddard, even when looking for it, at 

 first failed to find the ornamentation (2). This would reduce 

 P. bermudensis, arenae, insularis, ephippiger, and laccadivensis to 

 a single species. Some consideration should also be given to 

 P. matsushimensis , which possesses the same characteristic male 

 genital area ; though the absence of a distinct muscular prostatic 

 duct is perhaps a sufficient ground for separation. 



REFERENCES TO LITERATURE. 



1. Annandale, N. " The African Element in the Freshwater 



Fauna of British India," IXe Congr. 

 Zool., sect, iv, p. 587: Monaco ; 1914. 



2. Beddard, F. E. A Monograph of the order Oligochaeta : 



Oxford, 1895. 



3- >, in: The Fauna and Geography of the 



Maldive and Laccadive .Archipelagoes; 

 1903. 



4- >. '' On a new species of Worm of the 



genus Poniodrilus from the shores of 

 the Red Sea": Proc. Zool. Soc. 

 Lond., 1905, vol. ii. 



5. Michaelsen, W ,'' Oligochaeta " in: Das Tierreich; 1900. 



6. ,, " The Oligochaeta of India, Nepal, 



Ceylon, Burma and the Andaman 

 Islands": Mem. Ind. Mus., vol, i, 

 No. 3; 1909. 



