ENCHYTRAEIDAE 243 



glandular lobes, not covered on the outside by the muscular coat, are (in the sexually 

 mature specimen) 3 or 4 in number on one side and 7 on the other ; the largest is 28 by 

 36 /M as cut in section. (The gland masses were constantly two in number in Michaelsen's 

 specimens.) 



The species has been found in many various habitats, from purely marine (the canal 

 system of sponges) and littoral (amongst roots of seaweeds and the rubbish of the shore), 

 to purely fresh water (under stones in a pool) or more or less terrestrial (in moss). 



Marionina grisea, sp.n. (Figs. 4, 5). 



St. 189. 23. iii. 27. Port Lockroy, Wiencke Island, Palmer Archipelago. Shore coll. Three 

 specimens, one small and non-sexual, one found on sectioning to be not fully mature, one sexually 

 mature; along with LtimbriciUus maximus and L. lineatiis. 



The longest specimen measures 14 mm., the next 1 1 mm. ; diameter of the longest 

 0-68 mm. Segments 40, 33. 



The worms are pigmented black on the dorsum ; the pigment extends about as far as 

 the level of the upper border of the ventral setal bundles, though it is thinner in the 

 region between the lateral and ventral bundles. The pigment, while extremely dense 

 dorsally in the most anterior segments, is very scanty, though, as seen in sections, not 

 quite absent, in these segments ventrally. The youngest specimen is not so darkly 

 pigmented, and in it the pigment extends downwards on each side only to the level of 

 the lateral setae or very httle below this. The pigment is situated below, not in, the epi- 

 dermis ; in the youngest specimen it forms a branching and anastomosing network, as 

 if composed of branching chromatophores (though no nuclei are visible) ; in the largest 

 specimen, as viewed whole, the black pigment is largely broken up into discrete roundish 

 particles, though in some parts the chromatophore-like arrangement persists. In 

 sections, the pigment appears as a brown granular deposit on the inner side of the body 

 wall and in the muscular layer. 



The prostomium is short, rounded, hemispherical. A head pore is apparently present. 



The setae are lumbricilline in form ; the ventral bundles comprise (6) 7 (8) setae in 

 front of the clitellum, and the same number behind, falling at the hinder end to 4 or 5 ; 

 the lateral bundles contain 4 or 5 in front and about the same number behind the 

 clitellum. 



The clitellum extends over segments xii-xiii ; it is absent in the mid-ventral region. 

 There is in the sexually mature (but not in the early sexual) specimen, ventrally in 

 segment 10, a plate of thickened superficial epithelium, a single layer of tall cells, which 

 contrasts strongly in its regularity, flatness, and equal thickness over its whole extent, 

 with the thin (cubical or even lower) epithelium of the ventral surface of the segments 

 behind it, and also with the more irregular epithelium of the segments in front, raised in 

 a dome-like fashion (as seen in longitudinal sections) in each segment. The epidermis of 

 these anterior segments is only half as thick as that of the plate in x, 20 /x as against 

 40/x; while the thickness of the ventral epitheUum of segments xi and xii is less 

 again. 



