142 



HARDWICKE'S SCIENCE-GOSSIP. 



stone. With the exception of occasional bands of 

 cornstones, the nearest limestone rocks are at least 

 ten or twelve miles distant, across two or three 

 mountain ridges. The nearest habitat of P. calcareum 

 known to me is on the outcrop of the carboniferous 

 limestone, at least twelve miles away. Can any of your 

 readers inform me whether P. calcareum is found 

 elsewhere growing freely on non-calcareous rocks ? 

 Associated with the P. calcareum, Polystichum 

 letatum was fairly plentiful, but much less so than the 

 limestone polypody. There were also two or three 

 varieties of Cystopteris, a typical fern of these 

 mountains. I may add that I know the district in 

 question thoroughly, have searched it for ferns during 

 many years, but never found P. calcareum on the old 

 red before. — Thomas Jones, Newport. 



BOTANY. 



Geum intermedium in Sussex. — This plant, 

 •which has not hitherto been noted nearer to Sussex 

 than North Hants, has been lately met with at 

 Racton by Mrs. Hipkin, from whom I received 

 specimens. It has been observed that it usually 

 occurs in the vicinity of Geum rivale, and it was so 

 found there. There was, however, this peculiarity, 

 both flowers were growing on elevated and dry 

 ground, whereas all previous examples of the water- 

 avens which I have seen in Sussex grew in low and 

 damp situations. — F. H. Arnold. 



NOTES AND QUERIES. 



Change of Climate. — The part taken by the 

 goat in reducing fertile regions to the condition of 

 rainless deserts is now well recognised, and atten- 

 tion has lately been drawn to a similar part played by 

 the camel in Egypt. Is it possible that Peru was 

 anciently more fertile than at present, and that the 

 change has been brought about through the agency of 

 the llama or vicuna ? — J. R. Holt. 



Warning Colours. — There seems to me to be a 

 slight difficulty connected with the development of 

 warning colours, which possibly some of your readers 

 may be able to clear up. To make our ideas definite, 

 take the case of the Heliconias. Here an unpleasant 

 taste is associated with a peculiar coloration. Now, 

 either (1) the taste was developed first, and then the 

 colour, or (2) the colour first, and then the taste, or 

 (3) both were developed simultaneously. First con- 

 sider hypothesis (1). I do not quite see how the 

 taste could have been developed when the enemies 

 had no a priori means of discriminating between those 

 who possessed the taste and those who did not, as it 

 is obvious that the mere unpleasantness, which only 

 became obvious when the individual was killed, could 

 be no protection to the individual, whatever it might 

 be to the whole species. However, suppose the taste 

 was developed ; then on the first appearance of the 

 coloration, it would be suggested to the enemies that 

 this was another species, and presumably not so un- 



pleasant. So the coloration, instead of being a protec- 

 tion, would actually be the reverse, and would be sup- 

 pressed, instead of encouraged by natural selection. 

 Now take hypothesis (2). Supposing the colour 

 developed, the same difficulty as before arises with 

 regard to the development of the taste. Now take 

 hypothesis (3). This may be divided into two. 

 Either (a) the colour and taste, although developed 

 simultaneously, were independent, or (b) they were 

 connected. On supposition (a), the same difficulty 

 again arises. If unpleasant-tasting individuals did 

 not constitute a larger proportion of those who 

 possessed the coloration than of those who did not, 

 there would be nothing to connect the two in the 

 minds of the enemies, and neither the coloration, nor 

 the taste would be any effective protection. We thus 

 come to supposition (b), that the two were connected 

 or "correlated." But this again is in no sense an 

 ultimate, or even sufficient explanation. In the 

 majority of cases, it seems to me that " correlated " 

 is used as a convenient term to express our ignorance. 

 When two things are correlated, as far as I can see, 

 there must either (1) be a necessary connection 

 between them, and although this connection may be 

 difficult to trace, it is a proper subject for investiga- 

 tion, or (2) although there is no necessary connection, 

 between them, a connection has been established by 

 natural selection (or otherwise, possibly), and this, 

 establishment must have been prior to, and inde- 

 pendent of, the question under discussion at present. 

 And this again is a very proper subject for investiga- 

 tion.— J. R. Holt. 



Butterflies come Home to roost like 

 Poultry. — We were at Freshwater Bay ; the break - 

 last-room window looked into a long garden the width 

 of the house ; ivy grew all over the garden-walls. I 

 sat at the window one morning and saw a red ad- 

 miral butterfly come from under a leaf and, after flying 

 about a little, settle upon a German aster under the 

 window. I said to a lady in the room with me, 

 " There is the first admiral I have seen this season, 

 and I hope the poor thing is safe from being killed, 

 for he has lost nearly half of one of his lower wings ; 

 it spoils his beauty, though he can fly very well." 

 After [a bit he flew over the wall and away, and I 

 saw no more of him all day ; but chancing to be 

 looking out at butterfly bed-time, my friend came 

 back over the wall, and at once went to rest in the 

 place he had left in the morning. Of course I timed 

 him and kept a sharp look-out, and he was regular 

 for a week, and then one night he did not return, and 

 I saw him no more. I suppose a boy or a bird ended 

 his small life. I had, of course, noted many times 

 that the night-moths of various sorts fly at various 

 hours, but sleeping in the same place was new to me. 

 I have seen the sulphur butterfly do it in our own 

 garden for several days (since I noticed the admiral), 

 but that was the first time I noted it, and the fact 

 may be new to some of your readers. I can send you 

 one or two more short scraps of live things which have 

 come under my notice, if they are of any use to you 

 — but not of insects, as most particulars are known 

 to observing persons. 



A Talking Spider. — After an accident, being for 

 many weeks kept on a sofa in one position, also very 

 fond of natural history, and unable to sit up or work to 

 amuse myself, I kept a sharp look-out upon all the 

 insects which were kind enough to call upon me. I 

 was so still that nothing minded me, and they crept and 

 flew and settled and buzzed — the grand recipe for 

 making friends with all the pretty creatures is to be 

 quiet. My window was always open, my sofa close to 



