BENEATH TROPIC SEAS 



these the young pass through much of the swun- 

 miiig stage, with swimmerets developed, but func- 

 tioning only in ancestral memory. When at last 

 they are swept out of the sponge mouths, the 

 shrimplets are able to swim only for a brief period 

 and a short distance, and every atom of their 

 energy is directed toward finding a new, habitable 

 sponge. Death is the only alternative. Their 

 abbreviated youth ensures at least their continuing 

 in the vicinity where sponges presumably thrive. 



The odds of the game of fate and chance are fol- 

 lowed closely by the gods of the little shrimps, and 

 the play is to the limit. We can be fairly certain 

 that the difference between twenty, and five hun- 

 dred eggs expresses very exactly the ratio between 

 the dangers of a free-swimming life, and the 

 possibility, during a brief search, of finding and 

 diving into a life-long sponge sanctuary. If we 

 assume for argument, that in a single brood, the 

 annual increase of shrimps over the deaths is a 

 single individual, we know that at the most critical 

 time of life, four hundred and ninety -nine of the 

 free-swimming, snapping shrimps must succumb, 

 while of the sponge livers only nineteen fall by the 

 wayside. 



We can tramp about the sponges on the floor of 

 the ocean, and excavate their inhabitants; we can 

 watch these shrimps for a time in aquaria, and can 

 dissect their bodies, but it is only by such hints 

 as the difference in the size and number of eggs, 

 and the length or brevity of their youth, that we 



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