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The Museum Gazette 



tearing having taken place on each side of it. Although in 

 the first instance the sheathing membrane looked complete 

 and equally strong in all parts it was not really so, the rest 

 of the filaments did not cohere with this one as firmly as 

 they did with each other. 



We have now examined two most interesting arrangements 

 made for the protection of the young seed-vessel; first, the 

 keel formed by the petals, secondly, the sheath formed by the 

 stamens. We have seen how the latter is got rid of when it 

 has served its purpose, but there is yet a word to be said as 

 to what happens to the petals forming the keel. This struc- 

 ture withers like the other petals as the flower ages, but, 

 persevering in its mission, it does not at once fall off. It 

 loosens at its base and remains as a detached cap, covering 

 and protecting the end of the growing pod. Now and then it 

 fails to accomplish its detachment cleverly and may remain 

 fixed at one or other part of its base. When this happens 

 the cap over the end of the pod impedes its forward growth 

 and causes the pod to be bent backwards and twisted. If you 

 make search over a long row of peas you are almost sure to 

 find a few bent pods, and this is the way the bending is pro- 

 duced. Exactly the same sometimes happens with the " night- 

 cap " of the eschscholtzia. There is a difference, however, 

 between the eschscholtzia cap and that of the pea. The one 

 is the whole calyx, and the other two petals (the keel). 



It is impossible to contemplate the really wonderful arrange- 

 ments which we have described, and to remember at the 

 same time that they are the results of inheritance, without 

 accepting them as evidences of the long duration of time. 

 In all members of the pea family {Papilionacece) the protection 

 of the seed-vessel is accomplished on the same general plan, 

 but with endless minor modifications. These modifications 

 are transmitted from generation to generation, until some of 

 them become permanent and characterise a species. But 

 how slow must this process have been, and how vastly long 

 the period of time which has sufficed to accomplish and 



