THE BEISTLE-WORMS. 



115 



a hole in the sand. If the burrowing occur near the glass, 



the short tentacles (te) will be seen in addition to the 



golden bristles. When removed from its 



tube, the worm is seen to be short and 



stout, with relatively few segments, and a 



peculiar terminal plate (tp), which serves 



to close the posterior end of the tube. The 



prostomium bears tentacles like those of 



Terelella, and is much less conspicuous 



than the peristomium, which carries the 



bristles, and projects in the form of a 



collar. There are two pairs of gills (g). 



As in TerebeUa, the parapodia (p) are 



represented by dorsal clusters of bristles 



and ventral hooks. The worms do not 



quit their tubes except at the approach 



of death, but are capable of some amount 



,. , ' . r . ,, . , , .., FIG. 38. Pectinarut 



01 locomotion, carrying their tubes With belgica removed from 



them. In Terebella, on the other hand, %**&*% 

 the tubes are permanently fixed in one text. After Malm- 

 spot. 



Very different from Terebella or Pectinaria is the fisher- 

 man's lob-worm (Arenicola piscatorum), whose appearance 

 and habits we have already described. It is abundant in 

 most suitable places, except where incessant persecution has 

 almost exterminated it, and as bait has, or had, considerable 

 importance to fishermen. 



Though we have necessarily omitted many not uncommon 

 shore worms, there is one interesting if inconspicuous worm 

 which deserves special mention. This is Trophonia plumosa, 

 which is found not infrequently in muddy places on the 

 shore rocks. It varies in length from two to four inches, 

 and is a Northern form, which is both more abundant and 

 reaches a greater size in the Northern than in the Southern 

 waters of our islands. At first sight it may seem both an 

 uninteresting and a puzzling form, for there is almost nothing 

 in the external appearance to take hold of. The colour is a 

 dull drab, and the only striking character is the great pro- 

 jecting sheath of bristles at the anterior end. Nevertheless 

 the worm is interesting enough. The head is usually re- 

 tracted, but when protruded it is seen to bear two long 



