172 The Naturalist of Cumbrae. 



if you can find time to call as you pass through 

 Glasgow for Edinburgh." 



Some of our readers may be able to measure their 

 own knowledge of the subjects with which Mr. Robert- 

 son was familiar by attempting to assign to their 

 various natural orders the animals that happen to be 

 named in this short letter. The next is of a rather 

 different character. 



"4, Regent's Park Terrace, October 31, 1864. 

 "MY DEAR SIR, 



" I beg to acknowledge receipt of your 

 valuable present of Dr. Claus' book. I value it 

 greatly for two reasons : 



" First, as a pleasant remembrance of your short 

 stay at Cumbrae, and the great benefit that I derived 

 from your valuable instructions. There is one regret 

 that I may express connected with this pleasant 

 subject, that is, that I had not the benefit of those 

 instructions ten years ago. A timely index to the 

 proper path saves many weary wanderings. 



"And second, for its own intrinsic value. I find 

 that it treats on the very objects which I am, above 

 all others, interested in the copepoda. We have no 

 book, I may say, in the English language on this 

 subject. We have, no doubt, Dr. Baird's ' Natural 

 History of the British Entomostraca,' but it scarcely 

 touches on the marine copepoda. Although I find 

 difficulty in the language, the plates are so well 

 executed (and, I believe, quite trustworthy) that I 

 am managing to make the most of it available. 



