286 DISCOVERY REPORTS 



Subfamily DIPLOCARDIINAE 



Genus Dichogaster, Bedd. 



Dichogaster bolaui (Mich.) var. (Fig. zj-l). 



For complete synonymy and bibliography up to 1900, see: 



Dichogaster bolaui, Michaelsen, 1900, Das Tierretch, x, Oligochaeta, p. 340. 



Reference may also be made to : 



Dichogaster bolaui, Stephenson, 1923, The Fauna of British India : Oligochaeta, p. 472 (London). 



Annobon, found under stones near edge of lake, 13. viii. 27; three clitellate specimens, one of 

 which is very damaged, and a fragment. 



Length: the uninjured specimen is 69 mm., the other not badly damaged specimen is 

 without the tip of the tail but measures 58 mm. Maximum diameter 2 mm. Colour: 

 one specimen is slightly tinged with red-brown pigment dorsally on segments 2-8, also 

 the clitellum is red-brown; the other two specimens are apparently unpigmented. 



Clitellum saddle-shaped on segments 13-21 or I22. Copulatory papillae as median 

 ventral papillae at various intersegments (specimen i at 15/16 and 20/21 ; specimen 2 at 

 9/10, lo/ii, 15/16, 20/21, 21/22 and 22/23; specimen 3 at lo/ii and 15/16). Dorsal 

 pores: in the best-preserved specimen the first dorsal pore is visible at 5/6. Gizzards m 

 segments 6 and 7. Septa 4/5 and 5/6 present, 6/7 apparently absent. Last pair of 

 lateral hearts in segment 12. Nephridia in four rows on each side, sometimes a little 

 irregular. Seminal vesicles, two pairs in segments 11 and 12. Penial setal sac muscles 

 arise from the first intersegment behind their respective prostatic pores. Spermathecae : 

 the septa have slipped back so that the anterior spermathecae lie in front of septum 7/8, 

 the posterior pair partly in front of 8/9 and partly projecting into segment 9. Ovisacs 



present. 



Penial setae: in general the penial setae agree with the descriptions for this species, 

 but the size is unusually large and the distal end of the smooth seta forms a much less 

 conspicuous blade than usual. Setae of the a bundle are o-52-o-59 mm. long, 9^ in 

 diameter in the mid-region of the stem, narrowing to 4-5-5-5f^ towards the distal end; 

 the distal end ornamented with about 6 large teeth arranged in two rows, a seventh 

 smaller tooth may be present proximal to the others, and several of the more basal teeth 

 are double (Fig. 2;). Setae of the b bundle are o-46-o-5 mm. long, about 6;^ in diameter 

 in the mid-region of the stem narrowing to 3 or 4 ;u, towards the distal end, the distal end 

 is slightly flattened (4jli thick and 5-5 ;u. broad), the tip is flattened considerably but not 

 broadened {^fj- broad and ca. I^l thick), and terminates in a slightly notched edge 

 (Fig. 2 k, I); these setae are unornamented. 



In other characters these specimens are in essential agreement with the descriptions 

 of D. bolaui. 



Observations. In addition to the typical D. bolaui at least five different forms or 

 varieties of this species have been recognized, viz. palmicola Eisen, pacifica Eisen, 

 octonephra Rosa, decanephra Michaelsen and malabarica Stephenson. At least two other 



