302 



ANNELIDA 



Fig. 476 — 'A serpulid 

 projecting from its 

 tube (Cambridge Natu- 

 ral History). 1, gills ; 

 2, operculum ; 3, col- 

 lar ; 4, tube. 



Family 2. SEKPULIDAE. (Fig. 476.) 



Worms whicli 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 emploj'ed in smoothing 

 the inside of the shell: numerous genera and 

 species. 



Key to the genera of Serpulidae here described : 



fli Tubes incrusted on shells, etc 1. Hydroides 



O2 Tubes minute, spiral, usually on seaweed or shells. 



2. Spirorbis 

 C3 Tubes intertwining 3. Filograna 



1. 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, of tenest 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. 





Fig. 477 

 Hydroides hexagonus 

 (Hargitt) on a shell. 



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. 



