PELAGIC FLOATING CRUSTACEA 147 



The same result is produced if the surface is increased 

 by outstanding spines or hairs, just as, for instance, 

 a downy feather sinks slowly through the air, but 



FIG. 51 THE NAUPLIUS LARVA OF A SPECIES OF BARNACLE OF 

 THE FAMILY LEPADID^E, SHOWING GREATLY-DEVELOPED SPINES. 

 FROM A SPECIMEN TAKEN IN THE ATLANTIC OCEAN, NEAR 

 MADEIRA, x n. (After Chun.) 



drops rapidly if it is rolled into a ball between the 

 fingers. This is, no doubt, one function of the 

 spines with which plankton Crustacea, and particu- 

 larly larvae, are frequently provided, though they 



