ENCHYTRAEIDAE 241 



SYSTEMATIC 



Family PHREODRILIDAE 



Genus Hesperodrilus, Bedd. em. Michaelsen 



Hesperodrilus, sp. incert. 



St. WS 62. 19. i. 27. Wilson Harbour, South Georgia. From haul labelled " Moss dwellers " (so 

 on the label; in the Station List WS 62 is said to consist of two hauls, from 15-45 ^^'^ 26-83 m. 

 respectively). A single specimen, not fully mature; along with five specimens of LumbriciUiis 

 antarcticus . 



I am unable to identify the specimen; it seems, however, to be specifically distinct 

 from H. crozetensis, recorded from South Georgia by Michaelsen (1905). 



Family ENCHYTRAEIDAE 

 Genus Marionina, Michaelsen 



Marionina georgiana (Michaelsen) (Figs. 1-3). 



Pachydrilus georgianus, Michaelsen, 1888, p. 65, pi. ii, figs. 1 a,-] b. 

 Marionina georgiana, Michaelsen, 1905, p. 5. 

 Marionina georgiana, Michaelsen, 1905 a, p. 15, pi. i, fig. 2. 

 Marionina georgiana, Baylis, 1916, p. 298. 



St. MS 71. 9. iii. 26. From moss between Grytviken and Maiviken, East Cumberland Bay, 

 South Georgia. Six specimens, mostly non-sexual or in early sexual stage, one fully mature; along 

 with a single specimen of the genus Achaeta. 



Michaelsen largely supplemented his original account (1888) by the examination of 

 specimens from the Crozets (1905 o). The species appears to be somewhat variable, and 

 the following notes may add to our knowledge. 



Length 5-7 mm.; diameter o-3-o-35 mm., up to 0-4 mm. at the clitellum. Segments 

 37, 38, 32 (? complete), 30 (? complete), 27 (apparently complete). 



The setae are slightly lumbricilline in shape (i.e. with a slight double curve). The 

 ventral bundles contain (3) 4, 5 (6) in front of the clitellum, and (2) 3, 4 behind; the 

 lateral bundles have 2-4 setae both in front of and behind the clitellum. 



The clitellum, occupying segments xii-xiii, is very slightly marked, and is wanting 

 altogether ventrally. 



Postpharyngeal bulbs are present (for a discussion of these structures cf. Stephenson, 

 1922 a, or for a short general description, Stephenson, 1930). 



The dorsal vessel begins as a considerable swelling in segment xii. 



The anteseptal portion of the nephridium is small, but not very small ; it includes 

 more than merely the funnel, and is about half as long as the postseptal ; the duct is 

 continued backwards and then downwards from the hinder end of the organ. 



The cerebral ganglion is shown in Fig. i ; the shape scarcely agrees with that shown 

 by Michaelsen in his original account, being narrower in the middle and broader 

 behind, with the posterior lobes more rounded; but probably this only shows how 



