34 



DESIGN IN NATURE 



PLATE XVIII 



^ D 



Fin. 2. 



PLATE XX 



Fi(i. 3. 



Plate XX. illustrates temporary and permanent spiral formations in star-fishes and in the limbs, ribs, and 

 turbinated bones of vertebrates. 



Fig. 1. — Striking example of spirals formed by '•ho coiling of the limb,? of a brittlestar (Astninyx lovem). Tlie spirals resemble tliose 

 made by tlie tendrils of certain plants, for example the vegetable marrow (Plate ix., Fig. 1, B, 0) and passion flower (Plate x. 

 Fig. 1,7/, yh, M, mn, o, p). Drawn by C. Berjean from a photograph taken for the Author. 



Fig. 2. — Human ribs twisted upon themselves and forming thus spiials. The twist is indicated by the darts and letters a b and 

 c, d. Drawn by 0. Berjean from .specimens in the Author's museuiu. 



Fig. 3. — Portion of skeleton of Indian elephant (Ehqihas indicus) in the Museum of the Royal College of Surgeons of England. 

 Shows marked spirality in the bones of the left fore and left hind limbs, 



