170 TEANSACTIONS LIVEEPOOL BIOLOGICAL SOCIETY. 



Acoetes pleei, Euarche tubifex, and perhaps others) are 

 recorded as " dwellers in tubes ; " but any such habit on 

 the part of the northern form, Panthalis, appears to have 

 been unknown, and Kinberg, who describes and figures 

 the animal, makes no reference to it. 



From the fact that Panthalis when found off Port 

 Erin has always been associated with these mud tubes, 

 it seemed most probable that it was the maker of them : 

 still, this could only be accepted as a probability, and it 

 was obviously most desirable, that if possible, the question 

 should be definitely settled. 



The tube-masses, which are very soft, and easily pulled 

 asunder, are usually about 1J" to 1J-" in external diameter 

 by about 3J inches long, with loose mucus-like extensions 

 at either end, thus concealing the entrances. The 

 estimated internal diameter of the tubes is usually about 

 f". Careful examination, by sectionising, shews the 

 thickness of the walls in the centre to be about J" ; these 

 are composed of a number of thin layers ; the one nearest 

 the animal being simply a coating of mucus-like threads, 

 slightly sprinkled over with fine mud, followed by other 

 thin layers, distinguished by colours varying from dark to 

 reddish-brown, and consisting of a felty structure in which 

 mud is loosely entangled, until the outermost layer is 

 reached, which is generally of a drab colour, and very loose 

 in texture. In the early part of last year I embedded 

 portions of these tubes in paraffin, and prepared others by 

 staining, hardening and grinding-down, to form thin 

 sections, with the object of ascertaining, if possible, the 

 method of fabrication ; but these preparations, though 

 now valuable, at first afforded very little information, and 

 I was consequently wishful to observe the habits of the 

 living worm, an opportunity for which was last summer 

 afforded me by Professor Herdman. 



