494 THE . LOGARITHMIC SPIRAL [ch. 



of the florets in the sunflower; a true spiral, though not, by the 

 way, so easy of investigation, is presented to us by the outUne 



Fig. 237. The shell of Nmitilus jmm/pilius, from a radiograph : to shew the 

 logarithmic spk-al of the shell, together with the arrangement of the internal 

 septa. (From Messrs Green and Gardiner, in Proc Malacol. Soc. ii, 1897.) 



of a cordate leaf ; and yet again, we can recognise typical though 

 transitory spirals in the coil of an elephant's trunk, in the " circling 



