WORK AT THE SEASHORE. 269 



" difficulty of imagining how littoral sea-molluscs could 

 " cross tracts of open ocean, that islands, such as Madeira, 

 " must have been joined by continuous land to Europe ; 

 "which seems to me, for many reasons, very rash 

 "reasoning. Now, what I want to beg of you is, that 

 " you would try an analogous experiment with some sea- 

 " mollusc, especially any strictly littoral species — hatching 

 "them in numbers in a smallish vessel and seeing 

 " whether, either in larval or young shell state, they can 

 " adhere to a bird's foot and survive, say, ten hours in 

 "damp atmosphere out of water. It may seem a trifling 

 "experiment, but seeing what enormous conclusions 

 "poor Forbes drew from his belief that he knew all 

 "means of distribution of sea-animalcules, it seems to 

 " me worth trying. My health has lately been very in- 

 " different, and I have come here for a fortnight's water- 

 " cure. 



" I owe to using your name a most kind and most 

 " valuable correspondent, in Mr. Hill of Spanish Town. 



" I hope you will forgive my troubling you on the 

 " above points, and believe me, my dear sir, 



" Yours very sincerely, 



" Ch. Darwin. 



" P.S. — Can you tell me, you who have so watched all 

 14 sea-nature, whether male crustaceans ever fight for the 

 " females ? is the female sex in the sea, like on the land, 

 " ' teterrima belli causa ? ' I beg you not to answer this 

 " letter, without you can and will be so kind as to tell 

 " me about crustacean battles, if such there be." 



To this my father replied with ample notes, as, a little 

 later, he helped Darwin to collect facts with regard to 

 the agency of bees in the fertilization of papilionaceous 

 flowers. 



