334 BAMBLES OF A NATUEALIST. [Ch. XXI. 



the eye, although apparently aU the conditions for their 

 appearance are fulfilled. 



Indeed, the influences which cause marine animals of 

 the Mnds enumerated above to rise to the surface and float 

 upon the sea, would seem to be very obscure and capri- 

 cious. For although it is a rare circumstance that the 

 towing-net fails in securing some animals which would 

 otherwise have escaped observation, it is nevertheless com- 

 paratively seldom that they are m such numbers, or so 

 conspicuous, as to attract attention from the mere fact of 

 their floating ; and when they do so, it is not unfrequently 

 under conditions which would at first sight strike the 

 observer as anything but felicitous. Thus, when it is 

 considered how delicate is the texture, and how fragile the 

 structure of the majority of floating animals, it would at 

 once appear that fine weather and a calm surface would be 

 a combination of conditions most favourable to them. 

 The ripples and waves of a disturbed sea would be, to all 

 appearance, sufficient to mutUate or even to destroy such 

 tender animals. And yet calms are by no means the only 

 occasions on which they come to the surface ; indeed, they 

 exhibit a singular caprice in this respect. Thus, on one 

 occasion, in lat. 12° N. and long. 58° E., when the sea was 

 without a ripple, Porpitse, and various other Acalephs (jelly- 

 fishes) floated in considerable numbers, with occasional 

 Carinariee, and the water was moreover alive with myriads 

 of small Crustacea, which congregated in dense patches of 

 a reddish colour. The sunshine lighted them up — like 

 thousands of Httle sparks — as they rapidly darted about 

 just below the surface. But, on the other hand, when in 

 lat. 5° N. and long. 86° E., we experienced one of the most 

 perfect calms it has ever been my good fortune to witness, 



