36 GROWTH OF THE 'ORIGIN.' [ 1 84.6. 



turning so many reputed species into one. Have you ever 

 done anything of this kind, or have you ever studied Gloger's 

 or Brehm's works ? I was interested in your account of the 

 martins, for I had just before been utterly perplexed by 

 noticing just such a proceeding as you describe : I counted 

 seven, one day lately, visiting a single nest and sticking dirt 

 on the adjoining wall. I may mention that I once saw some 

 squirrels eagerly splitting those little semi-transparent 

 spherical galls on the back of oak-leaves for the maggot 

 within ; so that they are insectivorous. A Cychrus rostratus 

 once squirted into my eyes and gave me extreme pain ; and 

 I must tell you what happened to me on the banks of the 

 Cam, in my early entomological days : under a piece of 

 bark I found two Carabi (I forget which), and caught one in 

 each hand, when lo and behold I saw a sacred Panagcens crux 

 major I I could not bear to give up either of my Carabi, and 

 to lose Panag&us was out of the question ; so that in despair 

 I gently seized one of the Carabi between my teeth, when to 

 my unspeakable disgust and pain the little inconsiderate 

 beast squirted his acid down my throat, and I lost both Carabi 

 and Panagceus ! I was quite astonished to hear of a terres- 

 trial Planaria ; for about a year or two ago I described in the 

 ' Annals of Natural History' several beautifully coloured 

 terrestrial species of the Southern Hemisphere, and thought it 

 quite a new fact. By the way, you speak of a sheep with a 

 broken leg not having flukes : I have heard my father aver 

 that a fever, or any serioiis accident, as a broken limb, will 

 cause in a man all the intestinal worms to be evacuated. 

 Might not this possibly have been the case with the flukes in 

 their early state ? 



I hope you were none the worse for Southampton ; * I wish 



I had seen you looking rather fatter. I enjoyed my week 



extremely, and it did me good. I missed you the last few 



days, and we never managed to see much of each other ; but 



* The meeting of the British Association. 



