EXTRACTS FROM MR. DARWIN'S LETTERS. 457 



Art. XLIII. — Extracts of Letters from C. Darwin, Esq., to 

 Professor Henslow. 



PRINTED FOR PRIVATE DISTRIBUTION. 



" St. Iago (Cape de Verd Islands) is singularly barren, and 

 produces few plants or insects : on the coast I collected many 

 marine animals, chiefly gasteropodous mollusca (I think some 

 new)."— P. 3. 



" Rio de Janeiro. — I am now collecting fresh water and 

 land animals ; if what was told me in London is true ; viz. that 

 there are no small insects in the collections from the tropics, 

 I tell entomologists to look out, and have their pens ready for 

 describing. I have taken as minute (if not more so) as in 

 England, Hydropori, Hygroti, Hydrobii, Pselaphi, Staphy- 

 lini, Curculiones, Bembidia, &c. &c. It is exceedingly inte- 

 resting to observe the difference of genera and species from 

 those I know; it is however much less than I had expected. 

 I have just returned from a walk ; and, as a specimen how little 

 the insects are known, Noterus, according to Die. Class, 

 consists solely of three European species. I, in one haul of 

 my net, took five distinct species." — P. 5. 



" Monte Video. — I made an enormous collection of Arach- 

 nidse at Rio ; also a good many small beetles in pill boxes, 

 but it is not the best time of the year for the latter." — P. 5. 



" Amongst the lower animals, nothing has so much interested 

 me as finding two species of elegantly coloured Planarice (?) 

 inhabiting the dry forest ! The false relation they bear to 

 snails is the most extraordinary thing of the kind I have ever 

 seen. In the same genus (or more truly family) some of the 

 marine species possess an organization so marvellous that I can 

 scarcely credit my eyesight. Every one has heard of the 

 discoloured streaks of water in the equatorial regions. One I 

 examined was owing to the presence of such minute Oscilla- 

 toria, that in each square inch of surface there must have been 

 at least one hundred thousand present." — P. 6. 



" I might collect a far greater number of invertebrate 

 animals if I took up less time with each, but I have come to 

 the conclusion that two animals, with their original shape 

 noted down, will be more valuable than six with only dates and 

 place."— P. 6. 



NO. V. VOL. III. 3 N 



