8. THE TENTACULAR APPARATUS AND EXTERNAL DIGESTION 89 



When a living Siboglinum is examined under the microscope it is not un- 

 common to see parts of the tentacle coiled into a tight helix much smaller 

 than the diameter of the tube, while another portion is bloated with red blood 

 and occupies the whole width of the tube. I would suggest that such a region 

 represents a part of the tentacle where digestion of a trapped food particle is 

 taking place, digestion, that is, of a food particle picked up by a prehensile 

 tentacle, though in all fairness it should be added that Dr. A. J. South- 

 ward believes that the swollen parts represent damaged portions of the 

 tentacle.— D.B.C.] 



