FlGUKE it. 



One of the tube-forming Poly- 

 chsBtes, Sabella bombyx, slightly 

 enlarged. The specimen has 

 been removed from its tube, and 

 shows the crown of tentacles. 



[CH.ETOPODA.] 



H. HIEUDINEA. (Leeches.) 

 Worm-like animals, narrower at the 

 head end than at the tail, and having 

 a rounded sucker at each end. Ex- 

 ternal, temporary parasites mostly 

 found on vertebrates, sometimes 

 entering the mouth or nose ; living in 

 water (either fresh or salt) or on land 

 ill moist places, sometimes climbing on 

 to low bushes, &c. 



I. PHOEONIDEA (see Fig. 11). 

 Unsegmented worms living in tubes, 

 commonly found associated in large 

 numbers. Tube membranous, some- 

 times covered with mud and other 

 foreign 

 substances. 

 The mouth 

 is in the 

 middle of a 

 terminal 



crown of tentacles, arranged on a more 



or less obvious horseshoe-like plan. 



Alimentary canal U-shaped, the intestine 



running up by the side of the oeso- 

 phagus and opening near the mouth. 



The blood is red, with conspicuous red 



corpuscles. 



Marine. May be found attached to 



solid objects in shallow water, or 



inhabiting tunnels bored in calcareous 



rocks, shells, &c. 



J. ENTEEOPNEUSTA (see Fig. 

 17). Soft-bodied worms which may 

 have a strong odour of iodoform. The 

 front end has the form of a conical or 

 cylindrical "proboscis," which is 

 followed by a short region termed the 

 " collar," encirchng the mouth. The 

 rest of the animal, unsegmented and 

 often of considerable length, is composed 

 of several distinct regions, the first of 

 which is often produced into large 

 lateral flaps. A double series of pores figure lo. 



occurs on the back or at the sides of ^c/inrrw*- iM«;/aris, the "Spoon - 

 ,, . , , • 1 ,, • worm. slightly enlarged. 



this " branchial region. [Gephyee.\.] 



