316 MANUAL OF NATURAL HISTORY. 



elongated, cylindrical, rings indistinct; no 

 dermal appendages ; a few setae in place of 

 feet ; eyes on the head ; mouth simple. Live 

 in perforations of mud, in fresh water. 



10. FAMILY. Shore - Worms (Thalassematidae). 



Body soft, elongated, sub-cylindrical, annu- 

 late, obtuse behind, the posterior segments 

 spinulose ; two shining, hooked spines be- 

 neath the neck. Live in perforations of 

 sand, on the sea shore. 



11. FAMILY. L ob -Worms (Arenicolidae). Body 



with branchial, arbuscular appendages on the 

 middle ; segments with bundles of silky 

 bristles ; tentacles none ; head simple. Live 

 in the sand. 



12. FAMILY. Bristle-Worms (Chaetopteridae). Body 



with branchial appendages in form of small 

 laminae in a single series on upper sides of 

 body ; nine pairs of feet-like appendages, and 

 posteriorly a pair of long silky fasciculi. 



13. FAMILY. Aricians (Ariciidae). Body slender, 



with the gills in the form of broad laminae in 

 a series on each side ; feet-like appendages 

 with setae ; no posterior silky fasciculi. 



II. ORDER. SEDENTAKY- ANNELIDS (Tubicola). 



Body with soft appendages, for the most part col- 

 lected together at the anterior extremity ; feet usu- 

 ally of two kinds, without cirrhi ; head not distinct ; 

 without eyes or antennae. Living in attached tubes. 

 1. FAMILY. Amphitrites (Amphitritidae). Gills 



