MANUAL OF NATURAL HISTORY. 317 



pectinated, on the fore part of body; oral 

 tentacles numerous, filiform ; front of head 

 with golden spines, arranged crown-like or 

 comb-like. 



2. FAMILY. Terebellas (Terebellidse). Gills arbus- 



cular, on each side of mouth ; oral tentacles 

 numerous, filiform. Tube composed of grains 

 of sand and fragments of shells. 



3. FAMILY. Sabellas (Sabellidse). Fore part of 



body dilated, the sides fringed with setae ; 

 gills fan-like, on each side of mouth ; oral 

 tentacles pointed, not modified to serve as an 

 operculum. Tube composed of grains of clay 

 or mud. 



4. FAMILY. Tube- Worms (Serpulidse). Fore part of 



body dilated, fringed with setae; gills fan- 

 like, on each side of mouth; oral tentacles 

 unequal, one variously modified to serve as 

 an operculum. Tube calcareous, attached. 



II. SUB-CLASS. APODAL-ANNELIDS (Apoda). 



Body without bristles or feet-like organs for loco- 

 motion ; head not distinct, but generally provided 

 with eyes and jaws. 



I. ORDER. SUCTORIAL- ANNELIDS (Suctoria). 



Body soft, articulation obsolete or indistinct ; head 

 not distinct, but furnished with eyes and jaws ; or- 

 gans of locomotion in form of a sucker at one or both 

 extremities of the body. 

 1. FAMILY. True-Leeches (Hirudinidse). Body ob- 



