302 



ANNELIDA 



projecting from its 

 tube (Cambridge Natu- 

 ral History). 1, gills; 

 2, operculum ; 3, col- 

 lar; 4, tube. 



FAMILY 2. SEKPULIDAE. (FiG. 476.) 



Worms which live in calcareous tubes; arising from the prostomium 

 are a pair of large semicircular feathered gills which represent the 

 palps; an operculum usually present, composed of the dorsal gill fila- 

 ments; just beneath the gill filaments is the 

 collar, a paired membrane employed in smoothing 

 the inside of the shell: numerous genera and 

 species. 



Key to the genera of Serpulidae here described : 



Oj Tubes incrusted on shells, etc 1. HYDROIDES 



o 2 Tubes minute, spiral, usually on seaweed or shells. 



2. SPIRORBIS 

 a 3 Tubes intertwining 3. FILOGRANA 



Fig. 476 A serpulid i. HYDROIDES Gunnerus. Small worms living 



in long contorted tubes incrusted on shells, etc.; 

 funnel-shaped operculum present: several species, 

 1 in Woods Hole region. 

 H. hexagonus Bosc (H. dianthus Verrill) (Fig. 477). Color of gills 

 variable, oftenest a purplish-brown; length 75 mm.; diameter 3 mm.: 

 Florida to Cape Cod; very common. 



2. SPIRORBIS Daudin. A small worm living 

 in a tube coiled usually in a flat spiral, which is 

 incrusted on seaweeds, etc.; operculum present: 

 many species, 6 in the Woods Hole region. 



S. spirorbis (L.) (S. borealis Daudin). Coiled 

 tube 3 mm. across; length of animal 3 mm.; 9 

 gill filaments present; color of gills greenish- 

 white: Long Island Sound to Bay of Fundy and 

 northwards. 



3. FILOGRANA Oken. Small worms living in slender white tubes 

 which intertwine, forming masses 7 cm. high; 8 gill filaments present: 

 1 species in Woods Hole region. 



F. implexa Berkeley. Body compressed, 4 mm. long; tubes very 

 thin; color purple or pink: Maine to Vineyard Sound; Europe. 



SUBORDER 7. HERMELLIFORMIA. 



Peristomium very much enlarged and forming a setigerous bilobed 

 hood enclosing the prostomium, which bears a pair of tentacles and a 

 pair of palps ; the latter are fused with the ventral edges of the peristo- 

 mium and project in the form of numerous gill filaments from the hood ; 

 body composed of 2 regions, a thorax and a long tail-like abdomen which 

 has no parapodia and folds back on the thorax : 1 family and few species. 



Fig. 477 



Hydroides hexagonus 

 (Hargitt) on a shell. 



