TO A. HANCOCK, ESQ. 269 



No. 13. 

 (Postal date Jan. 12th, 1853.) 



Down Farnborough, Kent, 



Jan. lOth. 

 My dear Sir, 



I am uncommonly obliged to you for taking so much 



trouble as to write at such length to me ; though in truth, when 



I think of your many important pursuits in JS'atural History, I 



am ashamed to have lost you more than one good hour of time. 



"Your cautions and suggestions will be of considerable service 

 to me, as leading to fresh observations, and making me explain 

 some points more clearly. I will not take up your time in going 

 into several points you notice in this letter, but they shall all be 

 more or less attended to in my book. 



I may just inform you that when a ribbed shell is cut through 

 it can be seen that the marginal erosion* does not graduate into 

 the central hollow; indeed if the whole base was simultaneously 

 being eroded it is hard to see how the basal membrane and shell 

 could be firmly attached. I quite agree that more specimens on 

 calcareous and non-calcareous supports should be examined, and 

 I will write to a naturalist in Devonshire to collect for me. I 

 think, however, you did not understand that there were several 

 specimens on the two slate-rocks and hundreds on the Laminarise. 

 , I am quite delighted at what you say about my little friends, 

 the complemental males : I greatly feared that no one would 

 believe in them; and now I know that Owen, Dana, and yourself 

 are believers, I am most heartily content. I entirely agree with 

 you on your remarks on cross-impregnation. Some years ago I 

 set to work to collect facts on this head, but I have as yet done 

 nothing with them. Such a view as yours is the only foundation, 

 I am well convinced, to Steenstrup's rather wild Memoir on the 

 non-existence of Hermaphroditism in Nature, though he extends 

 the doctrine to mere physical organs ! 



. Many thanks for the wretched MS. returned. I am quite 

 sorry I asked for it, for I never dreamed that you had not long 



* Diagram in illustration given in letter. 



T 



