HARDWICKE' S SCIENCE-GOSSIP. 



whilst searching some Callitriche taken from one of 

 my aquaria that had been obtained in the previous 

 October from either Hayes or Keston. The first 

 impression was that it was CE. serfentinus, but careful 

 examination showed several discrepancies from the 

 description and figures given in Hudson and Gosse, 



Fig. 7S. — CEcistes, contracted. 



Fig. 79.— Trophi. 



Fig. 80.— Corona. 



viz., in the corona being reniform, the foot shorter, 

 tapering, more deeply and less regularly wrinkled, 

 and in its quiet habits. Neither does it agree with 

 the same author's meagre account of (E. fitygura, as it 

 certainly has a ventral antenna. It must come very 

 close to these two, but not being able to satisfactorily 

 determine which it is, I am induced to send my 

 drawing and notes to this widely read paper, in the 

 hope that some gentleman better versed in the 

 subject will be able to name it, or decide if it is a 

 new species. 



Ernest H. Tugwell. 



Greenwich. 



THE DEVELOPMENT OF THE COLOURS 

 OF FLOWERS THROUGH INSECT SE- 

 LECTION. 



THERE runs an old proverb that tells us that, 

 " He who proves too much proves nothing ; " 

 one that forcibly recurred to my mind as I read 

 Mr. A. G. Tansley's not unfair comments upon my 



paper anent the development of the colours of 

 flowers theory. 



Certain it is that, although he might fail to bring 

 conviction to my mind, if the establishment of the 

 theory depended upon his staunch and able advocacy, 

 he would, at least, win many to concurrence in his 

 views. Without going seriatim into these comments, 

 let me observe that, stripped of the verbiage and 

 technical phrases which too often encumber the 

 argument, it may manifestly be reduced to the 

 simple proposition that primitive flowers were 

 colourless, but that, through the selection of insects, 

 they have gradually acquired their present brilliant 

 colours. On the other hand, those not of this 

 way of thinking say, Not so, when we look around 

 us we see that from the germination of the seed, 

 through every stage of the plant's growth — through 

 its period of flowering — and on to its production of 

 mature seed colour is secreted. Sometimes either the 

 upper or the under side of the leaves, sometimes 

 both, are richly and permanently coloured, these 

 colours being often symmetrically disposed, as in 

 the case of flowers ; nor can it be said that these 

 bright colours are the attributes of a period of decay. 

 Often it is the young leaves or shoots alone, these 

 latter colours being more or less evanescent, and 

 ultimately assuming the tints of the parent stem and 

 branch. Then, again, we see the flowers of every 

 attractive hue, and, further on, the seeds often not a 

 whit less beautiful, sometimes even more so than the 

 petals of the flowers which produced them. Nor 

 does the secretion of pigments cease with growth- 

 reproduction, for it is seen also in the "red leaf." 

 Both in life and in death. 



Now whether we consider the whole period from 

 the germination of the old seed to the perfecting of 

 the new, a single process or a series of connected 

 processes, matters not ; 'tis throughout continuous, 

 nor can we say that at any particular point the 

 process is interrupted. 



Why then, it may be asked, why when the secretion 

 of pigments by plants is so universal should the 

 coloration from the beginning of the plant's life up 

 to its floral stage, and its further progress from 

 fertilization be recognised as chemical, or what not, 

 and yet the intermediate period — that of flowering — 

 be so arbitrarily excluded and, notwithstanding the 

 continuity of the process, be regarded as a period 

 entirely independent of that which precedes and 

 also of that which succeeds it ? 



The answer is given by the selectionist who has 

 discovered, or who thinks that he has discovered the 

 use of these flower colours, and who argues that, 

 assuming the benefits of cross-fertilization, which is 

 brought about mainly by the aid of insects, these 

 pigments "have a physiological significance of their 

 own," because their function is to attract these 

 insects, and although both plants and seeds too have 

 their functions these do not need colours, that is to 



