NOTE ON A NEW BRITISH ECHIUKOID GEPHYREAN. 381 



having branclied cloacal nephridia; while in all other respects 

 it either agrees with or comes nearer to Thai ass em a. 



Professor Lankester, after seeing one of my specimens and 

 hearing the details of structure as given above, has suggested 

 that I should describe this form as a new genus intermediate 

 between Hamiugia and Thalassema, and forming a term 

 in the series : Echiurus, Thalassema, the new form, Ha- 

 raingia, Bonellia. Professor Lankester^s opinion must 

 always carry great weight, especially in regard to this group 

 which he had already done so much to elucidate ; but in the 

 present matter I am inclined to think, from the consideration 

 of the characters given above, that my new form is distinctly 

 nearer to Thalassema than to Hamingia, and may without 

 any violence be included in the former genus. Consequently 

 I prefer to describe it as a new species of Thalassema, 

 related to T, gigas, M. MuUer, rather than to form an inde- 

 pendent genus for its reception. I desire to associate Professor 

 Lankester's name with this species. It seems appropriate, as 

 he has written on the two genera to which this form is related. 

 The specific diagnosis will run as follows : — 



Thalassema Lankesteri, n. sp. : 



Length about 20 cm. Proboscis nearly as long as trunk, 

 and in most of its extent wider. Tip of proboscis trun- 

 cated and slightly indented. Surface evenly tuberculated 

 all over. Colour apple-green on the trunk ; paler on 

 proboscis. Longitudinal musculature not divided into 

 bundles. A single pair of anterior nephridia; nephro- 

 stomes spirally twisted. Cloacal nephridia branched, with 

 numerous ciliated funnels on the ends of the branches. 

 Females alone known. Oflf Isle of Man, fifty fathoms. 

 As a species, T, Lankesteri is undoubtedly distinct from 

 the previously described species of Thalassema. Apart from 

 the anatomical peculiarities noted above, the external charac- 

 ters sufficiently distinguish the species. According to Lam- 

 port's and Rietsch's synoptic tables our form would be 

 grouped, from the characters of the body musculature and the 



