169 



[WORK FROM THE PORT ERIN BIOLOGICAL STATION.] 



OBSEKVATIONS on the TUBE-FOBMING HABITS 

 of Panthalis oerstedi. 



By Arnold T. Watson, Sheffield. 

 With Plates IX.— X. 



[Read January 11th, 1895.] 



On the 5th of June, 1893, when dredging with Professor 

 Herdman and the Members of the Liverpool Marine 

 Biology Committee on board the s.s. "Mallard," at a 

 depth of 60 fathoms, 14 miles West of Dalby (Isle of Man) 

 a number of long, curious, soft muddy masses were brought 

 to the surface, which in the absence of knowledge of their 

 character were promptly, and for the time being, appro- 

 priately described as "mud sausages." These masses 

 were at once carefully examined with the object of ascer- 

 taining whether they contained any tenant. The search 

 was unsuccessful, except as regards one mass, from which, 

 after long and careful manipulation under water, I 

 succeeded in expelling a living specimen of Panthalis 

 oerstedi, about 2 inches long. 



Since that time, a fair number of these mud masses 

 (which on examination proved to be mud tubes) have 

 been brought up when dredging in deep water off the 

 Isle of Man. Many of them were empty, but others 

 inhabited ; the most frequent tenant being Panthalis ; 

 and the question arose whether Panthalis was the 

 fabricator of the tubes, or simply a tenant ; and if the 

 former, by what method such curious heavy structures 

 were made. 



Panthalis is a Polynoid worm of the sub-family Acoe- 

 tidse, all the members of which are rare. A few of them, 

 dwellers in southern waters {Polyodontes maxillosus, 



