130 ANOTHER VISIT TO THE ANDAMANS 



ranging from 738 to 1091 fathoms; on all four occa- 

 sions the bottom brought up was ''green sand"; the 

 lowest bottom-temperature touched was 37°. 5 Fahr. 

 One of these hauls considerably damaged our gunner, 

 Mr Peterson, who, when the trawl was being hove in, 

 got his hand foul of the wire-rope in an attempt to 

 pick off the remains of some pelagic creatures that 

 were sticking to it. Luckily the lascar at the winch 

 was a sharp and experienced man, and reversed at 

 once, so that our zealous gunner escaped with a bad 

 cut and a few bruises, instead of having his arm torn 

 off. 



The results of these hauls consisted for the most 

 part of starfishes and moUusks of many kinds. Among 

 the latter was a handsome Pleurotoma, which we named 

 P. symbiotes, or "the partner," because the outside of 

 its shell was encrusted along both sides with small sea- 

 anemones of the genus Epizoanthus, That this associa- 

 tion of the two animals is no accidental circumstance, 

 but is a definite alliance for mutual benefit, is proved 

 by the facts, first, that we have not found these sea- 

 anemones on any of the other numerous species of 

 Pleurotoma dredged in these seas ; and secondly, that 

 on several subsequent occasions when this Pleuro- 

 toma has been taken, it has always had this particular 

 Epizoanthus upon its shell. 



Very boisterous weather betided us at and from 

 Colombo, and as we were fighting our way round 



I 



