TUBULIBRANCHIA. 653 



FIRST ORDER. TUBTTLIBRANCHIA, ( Tululicola, dwelling in tubes, 

 Cuvier.) SEDENTARY ANNELIDANS. 



These are characterized by having their branchiae in the 

 form of plumes, or of small tree-like figures, attached to the 

 head or fore part of the body. Nearly all inhabit tubes, which 

 are calcareous, sandy, or membranous. The order may be ar- 

 ranged into two families. 



First Family Serpulida, (Lat. serpula, a small snake.) 



Worms, the tubes of which are calcareous and singularly 

 twisted. They have the branchial tufts separated into two dis- 

 tinct parts by a pendunculated operculum, or else protected by 

 a solid one when they are drawn into the shell. 



1 . Serpula. This genus includes worms which adhere to stones, 

 shells, and other sub-marine substances. The branchiae are of 

 a beautiful red, or variegated with yellow and violet, and used 

 in taking the minute living objects upon which the worm sub- 

 sists. They are found in the Mediterranean and European seas. 

 This genus has been estimated to embrace sixty or more re- 

 cent and fossil species. (Fig. on Chart.) 



2. Vermilia, Worms so named from the red line on each side 

 of the ridge which appears upon the back. (Plate XVI. fig. 5.) 



3. Ditrupa, Worms free, living in a tubular shell, open at 

 both ends, with twenty -two branchiae, in two sets, and feathered 

 with a row of cilia. These are nearly allied to the Serpula. 



SECOND FAMILY, Amphitritida* 



Worms which have around the mouth numerous thread-like 

 tentacles ; and tubes formed by a mucous secretion to which are 

 attached fragments of shells, etc. 



1. Amphitrite. These have the thread or straw-like processes 

 in the form of a comb or that of a crown. 



2. Sabetla, Worms about the size of a finger, living in tubes 

 composed of sand, clay or fine mud. The plumes are highly 

 brilliant and delicate, sometimes of a rich orange color. 



3. Terebella, Worms living in tubes of similar composition 

 with the preceding, having on the neck arborescent, not fan-shaped 

 gills. 



