412 OLIGOCHAETA 



(24) Perichaeta barbadensis, Beddaed. 



p. barbadensis, Beddard, loc. cit., p. 167. 



Definition. Length, 105 mm.; ireadth, 4 mm.; number of segments, 78. Clitellum XIV- 

 XFI, with setae on some of the segments. Male pores quite lateral in position,, 

 separated hy diameter of body. Oenital papillae variable in number ; some in neighbour- 

 hood of male pores, and occasionally one in neighbourhood of spermathecal pores. Setae. 

 Egg-sacs in XIII, XIV. Spermathecae in VI, VII, and (sometimes) VIII. Spermiducal 

 glands extensive, reaching from segments XVII-XXI ; no terminal sac. Sab. — Barbadoes. 

 In my description of this species three individuals were described. All of these 

 differed in some particular from each other ; hence it is a matter of guess-work to 

 abstract the specific characters. The variations affect the setae upon the clitellum, 

 the genital papillae and the number of the spermathecae. The following are the 

 characters of the three individuals : — 



I. About six setae upon the last segment of the clitellum^. A median papilla 



upon segment vii, just in front of setae, and another papilla occupying 



a corresponding position on segment xviii. Spermathecae in vi, vii. 



a. Setae (about nine in number) on last segment of clitellum. On segment xviii 



two papillae on each side to inner side of atrial pore. Three pairs of 



spermathecae in vi-viii. 



3. Setae on last segment of clitellum about as numerous as in a ; also setae three 



or four in number on segment xiv. Papillae complicated ; on xviii ' a small 



circular papilla lies above each atrial pore and another lies exactly below it, 



on the boundary line between segments xviii/xix. In the middle of segment 



xviii are two papillae lying side by side and above the setae of that segment. 



On the right-hand side of the body is another papilla, which lies just above 



one of these two. There are thus seven papillae in all.' Spermathecae 



in vi, vii. 



These differences cannot be accounted for by differences in age. It is true that, 



as in Typhoeus orientcdis for example, the genital papillae do differ in individuals, 



the difference being very possibly one of maturity ; but in the present instance there 



is no sort of correspondence between the variations in the genital papillae and in the 



variations of the clitellar setae. In immature worms, which have no setae upon the 



clitellum, when fully mature the segments that will be subsequently modified into 



the clitellum have their full complement of setae ; it might therefore be suggested 



' More are (erroneously) represented in my illustration (loc. cit. PI. ix, fig. 6). 



