350 Miscelldneous. 



It differs materially from any of the vast numbers oi Helices now known 

 to conchologists, especially in the different character of the upper 

 and lower parts of the shell. The upper portion of the whorls has 

 a rough rusty surface encircled by numerous finely beaded lines and 

 keels ; the lower surface is smooth and shining, jet-black, encircled 

 by a distinct yellow band. — Proc. Zool. Soc. Feb. 24, 1852. 



On th0 Colours of Plants. By M. Martens. 



At the close of a long memoir on this subject, the author gives the 

 following summary of his results : — 



1 . The only two fundamental or primitive colours in plants are 

 blue and yellow, or in other words anthocyane and anthoxanthine. 



2. These primitive colouring matters are formed under the vita^ 

 influence, not only in the petaloid, but also in the herbaceous por- 

 tions ; in the latter they are most frequently associated together and 

 with other organic matters, thus forming the insoluble green chloro- 

 phylle. 



3. Chlorophylle always has a tendency to become yellow in plants 

 in consequence of the great alterability of the blue colouring principle, 

 unless the latter has been rendered more stable by union with an acid 

 which reddens it. In this case the leaf, instead of acquiring a yellow 

 colour by the alteration of the chlorophylle, becomes red. 



4. The red colour of leaves is not always the result of the presence 

 of an acid, whether by the action of this upon the blue or upon the 

 yellow colouring principle of the leaves. The red matter of the 

 leaves, the so-called erythrophylle, may also arise from the oxygena- 

 tion of the yellow principle or xanthophylle. 



5. The blue and yellow colouring matters, especially the former, 

 being often, when isolated, in a liquid state, must be carried in this 

 case by aqueous transpiration towards the surface of the plant, by 

 which means they must become deeper in colour, or more concen- 

 trated, in the cells which lie immediately under the epidermis, where 

 they are constantly met with, and where they may also be subjected 

 to the action of oxygen. 



6. Although the coloured juices usually exist in the most super- 

 ficial layers of cells, in which the chlorophylle is scanty, they may 

 nevertheless arrive there from more internal cells by the action of en- 

 dosmose and exosmose. 



7. In proportion as the blue, yellow or red colouring juices appear 

 in the cells of the herbaceous parts, the quantity of chlorophylle di- 

 minishes ; it may even disappear entirely when the petaloid colora- 

 tion becomes very intense, as in the red cabbage. 



8. Chlorophylle, being capable by its decomposition of giving rise 

 to blue and yellow matters, may assist indirectly in the formation of 

 the colours of flowers as well as of coloured leaves. 



9. The colours of flowers can only change according to the varia- 

 tions of which the blue and yellow are capable. Now blue is able 

 to pass to red by means of acids, and also to present all the colours 



