ANIMAL LIFE OF THE SHORES 295 



a Malay and I attacked with large mattocks one of 

 these cones ; at the end of an hour the Malay was 

 knee-deep in water in a long trench that he had cut 

 along the track of the Crayfish's burrow, and I could 

 hardly see the man's back for the crowd of mosquitoes 

 on it, while my own hands were too busily employed 

 in brushing mosquitoes off my person to permit me to 

 dig at all. As the end of the burrow seemed as far 

 off as ever, we retired defeated from the field. The 

 investigation of a mangrove-swamp fauna I decided 

 henceforth to leave to some other naturalist endowed 

 either with the skin of a rhinoceros or with an 

 enthusiasm that could rise superior to acute physical 

 discomfort. The stems of the Nipa-palms that grew 

 in this swamp were closely studded with peculiar flat 

 shells that presented a sufficiently near resemblance 

 to shells of Lingula, a Brachiopod that has persisted 

 from the most ancient geological times to the present 

 day, to lead me at first to think that I had made a 

 great find. A closer examination, however, showed 

 that these were the shells of a true Mollusc belong- 

 ing to the Anomiacea, a sub-order that includes the 

 common Anomia ephippium (Linn.) of Europe and is 

 related, though distantly, to the Oysters. The name of 

 this mollusc, /Enigma cenigmatica, shows that it had 

 puzzled naturalists before me. The shell is a bivalve ; 

 the left valve, which is the only one that the observer 

 can see before the animal is removed from the palm- 

 stem to which it is attached, is elongate-oval, dark 

 purplish-red in colour, very thin and more or less 

 translucent ; the right valve is much smaller, white, 

 transparent, and very delicate ; it is perforated in 

 the middle, and through the hole passes a structure 



