480 



OLIGOCHAETA 



This genus IB to be distinguished by two very salient characters: (i) the large 

 number of intestinal caeca, which entirely resemble the single pair of Perichaeta ; 

 and (2) the nephridia; the latter are anteriorly of the ordinary diffuse kind; 

 posteriorly, apparently entirely through the inordinate growth of the vesicular 

 peritoneal cells, each segment appears to be filled with a row of small oval sacs ; these 

 are merely the disguised nephridia. 



(i) Millsonia rubens, BEDDAHD. 

 M. rubens, BEDDAED, P. Z. S., 1894, p. 382. 



Definition. Length, 320 mm. ; diameter, 12 mm. ; number of segments, 363. Male pores 

 paired. Clitellum, XIII-XXII. Spermathecae in VIII. Sperm-sacs in XI, XII. No 

 hursa copulalrix. Hab. Tropical W. Africa. 

 The brick-red colour of the worm (in alcohol) suggested its name. The septa 



begin iv/v, but ix/x is the first which is thickened. The first five segments appear 



to be without setae (cf. Deodrilus). 



(2) Millsonia nigra, BEDDARD. 

 M. nigra, BEDDAED, loc. cit., p. 385. 



Definition. Length, 230 mm.; diameter, 7 mm. Male pores single. Spermathecae in I'll, 

 opening VIII/IX. Spermiducal glands open each into a bursa copulatrix. Hab. 

 Tropical W. Africa. 



The colour of the preserved worm is a very dark brown. As in the last species, 

 there are dorsal pores. The distal end of the sperm-ducts has a muscular sheath, and 

 opens separately from the spermiducal gland into the bursa. The latter is a thick- 

 walled sac, something like that of Oeoscolex, and seven mm. long. The Spermathecae 

 perforate septum vii/viii, and come to lie in the former segment, though the external 

 pore is between viii/ix. The very first septum (iv/v), and thence to xiii/xiv, are 

 thickened. 



Genus PLETCHBRODRILUS, MICHAELSEN. 



Syn. Cryptodrilus, FLETCHEB (in part.). 



DEFINITION. Setae in eight rows. Male pore and spermathecal pores in a single 

 median unpaired series. Nephridia paired. Spermiducal glands tubular. 

 Spermathecae one to each segment, with a pair of diverticula. No penial 

 setae. 



