246 DISCOVERY REPORTS 



wards occupy the upper part of the lumen. The change in character of the Hning 

 epitheHum, tall in the bulb (duct), low in the ampulla, is quite sudden. There are two, 

 or sometimes three, glands in connection with the duct, attached to its lower portion. 



There is a copulatory gland in segment xv, of some size, consisting of two halves, one 

 on each side of the cord ; each half is bilobed, the lobes being anterior and posterior, and 

 the cord is not in the least covered over, the dorsal surface being quite free ; indeed the 

 gland does not invest the cord closely even at the sides, the two halves being thus quite 

 separate. The gland rises up to a height of loo/x above the inner surface of the body- 

 wall — double the height of the upper surface of the cord — but still does not reach the 

 level of the gut. 



The relations of this species will be considered along with those of the next. 



Marionina aestuum, sp.n. 



II. i. 27. Shore of Bay of Isles, South Georgia; from Ulva sp. between tide marks. Several 

 specimens, some sexual; along with Enchytraeus colpites. 



The length of the sexual specimens is 11-12 mm., and their diameter o-6 mm., or 

 slightly more at the clitellum. Segments 46, 47, 48. 



The prostomium is short and rounded. 



This, like the last, is a pigmented species ; the pigment varies in depth from light to 

 dark grey, and extends from the dorsal surface downwards on each side as far as the 

 level of the ventral setae, or more densely to the level of the lateral setae and thence more 

 lightly to the ventral setae. On a casual examination it appears never to extend all round 

 the body ; but a careful inspection in cedar oil showed that in the most anterior segments 

 a number of scattered chromatophores are present in the ventral region also. As seen in 

 sections the brown branched chromatophores are quite below the epithelium, in the 

 longitudinal muscular coat and especially in a layer on the inner surface of this coat. 



The setae are lumbricilline in shape, and are rather uncommonly numerous in each 

 bundle. The ventral bundles comprise 14-17 setae in front of the clitellum; behind, 

 8-15 are found, the higher number only occasionally, the lower usually towards the 

 hinder end of the body. The lateral setae are 8-13 per bundle in front of the clitellum, 

 and 7-9 behind. 



The clitellum, occupying segments xii-xiii, is saddle-shaped, very thick dorsally, 

 absent ventrally, and lighter in colour than the neighbouring segments ; there is a ventral 

 groove between the well-marked lower border of the clitellum on each side; and the 

 male porophores, situated at this lower border, look almost inwards. The appearance 

 varies somewhat, however, probably with the degree of contraction of numerous 

 muscular bands internally in this region. There is no ventral thickened cutaneous plate 

 in segment x, as in M. grisea. 



The epidermis contains very numerous and closely set gland cells, staining so deeply 

 blue (with haematoxylin) as to appear black ; indeed for a moment on iirst looking at the 

 sections I doubted if the colour of the worms might not be due to these cells. The depths 

 of the intersegmental grooves, and the areas immediately surrounding the setal bundles. 



