300 ANNELIDA 



20 pairs of green, short tentacular filaments which act as gills; palps 

 large; proboscis unarmed; blood green; setae of the anterior segments 

 often very long and projecting directly forwards: 6 genera. 



1. TROPHONIA Milne-Edwards. Anterior setae pro- 

 longed, enclosing the head: 2 species in the Woods Hole 

 region. 



T. affinis (Leidy) (Fig. 474). Body slender and 

 elongate; 8 tentacular filaments on head, which are blunt 

 and of unequal length; length 6 cm.; width 3.5 mm.: 

 Vineyard Sound and New Jersey; in 20 fathoms. 



SUBORDER 6. SABELLIFORMIA.* 



Fig. 474 

 T affinis a Prostomium more or less hidden by the forward 



extension of the peristornium which usually forms a 

 projecting collar; tentacles rudimentary or very small; 

 palps very large, forming the branchial crown; proboscis present; body 

 consisting of 2 regions, a thorax of about 9 segments, and an abdomen; 

 worms tubicolous: 4 families. 



Key to the families of Sdbelliformia here described: 



Oi Tubes membranous ....................................... 1. SABELLIDAE 



Oa Tubes calcareous ......................................... 2. SEBPULIDAE 



FAMILY 1. SABELLIDAE. 



Worms which live in membranous tubes in mud and sand; arising 

 from the prostomium is a pair of large semi-circular feathered gills rep- 

 resenting the palps, which may be surrounded by a collar formed of the 

 peristomium; tentacles rudimentary or hidden; parapodia very rudi- 

 mentary: many genera. 



Key to the genera of Sabellidae here described : 



! Peristomial collar present. 

 &! Collar lobes separated dorsally .............................. 1. SABELLA 



6 2 Collar lobes meeting dorsally .............................. 2. POTAMILLA 



a 2 Collar absent. 

 &! Worms live in gelatinous masses ; no eyes ................... 3. MYXICOLA 



6 2 Worms live in distinct tubes ; eyes present. 

 c t Worms in fresh water ................................ 4. MANAYUNKIA 



c 2 Worms marine ........................................... 5. FABBICIA 



1. SABELLA Malmgren. Gill filaments long and slender; peristo- 

 mium raised and reflexed to form a collar around the gills which is 

 notched dorsally: many species. 



* See "Tubicolous Annelids of the Tribes Sabellides and Serpulides from the 

 Pacific Ocean," by K. J. Bush, Harriman Alaska Exp., Vol. 12, 1910. 



