1 857.] VARIABILITY. 99 



in the law ; I have had so many instances, as the following : 

 I wrote to Wollaston to ask him to run through the Madeira 

 Beetles and tell me whether any one presented anything very 

 anomalous in relation to its allies. He gave me a unique case 

 of an enormous head in a female, and then I found in his book, 

 already stated, that the size of the head was astonishingly 

 variable. Part of the difference with plants may be accounted 

 for by nrany of my cases being secondary male or female 

 characters but then I have striking cases with hermaphrodite 

 Cirripedes. The cases seem to me far too numerous for 

 accidental coincidences of great variability and abnormal de- 

 velopment. I presume that you will not object to my put- 

 ting a note saying that you had reflected over the case, and 

 though one or two cases seemed to support, quite as many 

 or more seemed wholly contradictory. This want of evidence is 

 the more surprising to me, as generally I find any proposition 

 more easily tested by observations in botanical works, which 

 I have picked up, than in zoological works. I never dreamed 

 that you had kept the subject at all before your mind. Alto- 

 gether the case is one more of my many horrid puzzles. My 

 observations, though on so infinitely a small scale, on the 

 struggle for existence, begin to make me see a little clearer 

 how the fight goes on. Out of sixteen kinds of seed sown on 

 my meadow, fifteen have germinated, but now they are 

 perishing at such a rate that I doubt whether more than one 

 will flower. Here we have choking which has taken place 

 likewise on a great scale, with plants not seedlings, in a bit of 

 my lawn allowed to grow up. On the other hand, in a bit of 

 ground, 2 by 3 feet, I have daily marked each seedling weed 

 as it has appeared during March, April and May, and 357 have 

 come up, and of these 277 have already been killed, chiefly by 

 slugs. By the way, at Moor Park, I saw rather a pretty case 

 of the effects of animals on vegetation : there are enormous 

 commons with clumps of old Scotch firs on the hills, and 

 about eight or ten years ago some of these commons were 



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