collected in the Sea of Spitzhergen. 57 



structure which evidently represents the variously formed pro- 

 cesses of many Serpulacean opercula. Future observers will 

 also have to take into consideration whether the operculum of 

 Scione, like that of many Serpulacese, plays any part in the 

 business of reproduction. 



It still remains to be noticed as remarkable that this struc- 

 ture is not mentioned by Malmgren, who is so circumspect, 

 especially as it is evident that he had before him numerous 

 specimens of the worm from various localities. I cannot sup- 

 pose that in my case we have to do with a structure produced 

 by accident, or one which is to be regarded as a singular mal- 

 formation, which has led, in this instance, to the formation of 

 an organ analogous and homologous with the operculum of 

 the Serpulacese. Here, also, the examination of more abun- 

 dant material will decide whether the occurrence of the oper- 

 culum in this worm is unexceptional, or on what conditions it 

 depends. 



Ereutho Smithi (Malmg.). Storfjord. 



TerebelUdes Stromii (Sars). Storfjord. 



Sahella spetshergensis (Malmg.). Zweigletscherbucht. 



Potamilla, sp. Zweigletscherbucht. 



Of this genus, established by Malmgren, of which no Spitz- 

 bergen species has hitherto been known, I have an animal 

 before me which I cannot identify with any of the described 

 species. The description given by Malmgren of Potamilla 

 neglecta (Sars) suited it best ; and I should probably have en- 

 tertained no doubt of having to do with that species, had not 

 the proportions of the body been quite different from those of 

 the above-mentioned species. For whilst in the latter the 

 branchiae are nearly half as long as the rest of the body, they 

 are considerably smaller here ; for the body, consisting of 30 

 segments, measuring 20 millims. in length, whilst even the 

 last segments are deficient, bears a branchia only 4 millims. 

 long. The tube consists of a membrane which is for the most 

 part coated with sand-grains and fragments of various kinds, 

 and also in part possesses a muddy coat. The single specimen 

 before me, which, moreover, is not uninjured, does not suffice 

 to make sure whether we have to do with a new species or 

 what its characters are. 



Euchone rubella^ n. sp. Advent Bay. 



Body colourless, stout, of uniform thickness throughout its 

 length, consisting of 34 segments, 30 millims. in length, 2 

 millims. in breadth, with short branchiae 3 millims. in length. 

 First segment with the straightly extended gorget, which is 

 but slightly emarginate on the ventral surface, nearly as long 

 as the four following, concave in the middle of the ventral 



