86 WORMS, ROTIFERS, LEECHES, POLYZOA 



All the Tube -building Worms are beautiful and interesting 

 creatures, and of one of these, the Sabella, Sir John Dalyell has 

 left among his writings the following description : " Let a tall 

 and ample crystal jar containing a Sabella be emptied of its con- 

 tents and speedily replenished with sea-Water ; the animal, if in 

 view, has retreated during the short interval ; the orifice of the 

 tube is closed ; all is at rest. But soon after replenishment it 

 rises, to display its branchial plume still more vigorously than 

 before, and remains stationary, as if enjoying the freshness of 

 the renovated element, always so grateful the harbinger of 

 health and strength to those whose dwelling is there. The passing 

 spectator would conclude that he now beholds only a beautiful 

 flower, completely expanded, inclining towards the light like some 

 of those ornaments of Nature decorating our gardens. He pauses 

 in admiration. But if a drop of liquid mud falls amidst the 

 element from above, disturbing its purity, then, while the plume 

 unfolds to its utmost capacity, does the animal commence a 

 slow revolution, the body also passing around within the tube. 

 Now are the thousands of cilia fringing the ribs of the branchiae 

 discovered to be in vigorous activity, and their office to be won- 

 drous. A loose muddy mass is soon afterwards visibly accumu- 

 lated in the bottom of the funnel ; meantime the neck, or first 

 segment of the body, rising unusually high above the orifice 

 of the tube, exhibits two trowels beating down the thin edge 

 as they fold and clasp over the margin, like our fingers 

 pressing a flattened cake against the palm of the hand. 1 

 During these operations muddy collections are seen descend- 

 ing between the roots of the fans towards the trowels ; while 

 another organ, perhaps the mouth, is also occupied, it may be, 

 in compounding the preparation with adhesive matter. Still 

 does the partial or complete revolution of the plume above, 

 and of the body within the tube, continue ; the bulk of the 

 muddy mass diminishes, activity abates ; it is succeeded by 

 repose, when the tube is found to have received evident prolonga- 

 tion." 



Amphiglena mediterranex is a handsome little worm, only J inch 

 long, and when seen alive under the microscope is very beautiful, 

 ; ts plume-like gills, clad with a double row of ciliated processes, 



1 This refers to the curious lappets of the peristomial collar. 





