142 EVOLUTION [CHAP. Ill 



Letter 95 find were not in allied groups. Trees like Aspicarpa^ with 

 flowers of two kinds (in the Origin)^ led me also to speculate 

 on the same subject ; but I could find only one doubtfully 

 analogous case of species having flowers like the degraded 

 or monstrous flowers. Harvey does not see that if only 

 a few (as he supposes) of the seedlings inherited being 

 monstrosities, Natural Selection would be necessary to select 

 and preserve them. You had better return the Gardeners' 

 Chronicle, etc., to my brother's. The case of Begonia 2 in itself 

 is very curious ; I am tempted to answer the notice, but I will 

 refrain, for there would be no end to answers. 



With respect to your objection of a multitude of still 

 living simple forms, I have not discussed it anywhere in the 

 Origin, though I have often thought it over. What you say 

 about progress being only occasional and retrogression not 

 uncommon, I agree to ; only that in the animal kingdom I 

 greatly doubt about retrogression being common. I have 

 always put it to myself What advantage can we see in an 

 infusory animal, or an intestinal worm, or coral polypus, or 

 earthworm being highly developed ? If no advantage, they 

 would not become highly developed : not but what all these 

 animals have very complex structures (except infusoria), and 

 they may well be higher than the animals which occupied 

 similar places in the economy of nature before the Silurian 

 epoch. There is a blind snake with the appearances and, in 

 some respects, habits of earthworms ; but this blind snake 

 does not tend, as far as we can see, to replace and drive out 

 worms. I think I must in a future edition discuss a few more 

 such points, and will introduce this and II. C. Watson's 

 objection about the infinite number of species and the 



1 Aspicarpa, an American genus of Malpighiaceae, is quoted in the 

 Origin (Ed. VI., p. 367) as an illustration of Linnaeus' aphorism that 

 the characters do not give the genus, but the genus gives the characters. 

 During several years' cultivation in France Aspicarpa produced only 

 degraded flowers, which differed in many of the most important points 

 of structure from the proper type of the order ; but it was recognised by 

 M. Richard that the genus should be retained among the Malpighiaceas. 

 "This case," adds Darwin, "well illustrates the spirit of our classifi- 

 cation." 



2 Harvey's criticism was answered by Sir J. D. Hooker in the 

 following number of the Gardeners' Chronicle (Feb. 25th, 1860, p. 170). 



