182 TBANSACTIONS LIVEKPOOL BIOLOGICAL SOCIETY. 



somewhat like the ribs of an umbrella which has been 

 turned inside out. Often these ribs are partially closed 

 up, and shew no movement, but I have several times seen 

 them when at work opening and closing, probably by the 

 pull of the threads and the resistance of the water. It 

 should be noticed that the " brush-like " setae are attached 

 only to the parapodia possessing " spinning -glands" and 

 their use is at once obvious. All the setae in Panthalis 

 proceed from the ventral lobes of the parapodia; the 

 position of these brush-like bristles, as described by Kin- 

 berg is uppermost ; they are capable of very considerable 

 extension and also of being retracted almost entirely 

 within the body of the animal; the threads from the 

 " spinning gland " issue from the cleft between the upper 

 and lower lobes of the parapodia, i.e., just against these 

 setae, and they are caught-up and carried outwards and 

 forward by the action of these brushes assisted, to some 

 extent, in the latter movement by other setae. I have 

 seen this actually take place, and on examination of dead 

 specimens the observation is confirmed, the brush -like 

 setae being frequently found directed forward with masses 

 of threads entangled in them. 



The parapodia possessing " spinning glands " are en- 

 dowed with all three kinds of setae mentioned by Kinberg ; 

 but the six pairs between the last " spinning gland " and 

 the ''weaving feet" have two kinds only, the brush-like 

 setae being replaced by a second set of serrulate setae 

 similar to those figured by Kinberg for Eupompe. 



The foregoing, I think, describes fully the formation of a 

 single thin tube ; but it will be remembered that the 

 tube inhabited by Panthalis is quarter of an inch thick, 

 composed of many apparently parallel layers, formed one 

 inside the other, and I therefore still had some difficulty 

 in understanding how this strong, heavy structure could 



