Number of Fibrils in the Cilia of the Green Algæ

Abstract

READERS of Nature who may have noticed the simultaneous appearance in the issue of February 14 of two independent communications^1,2 on plant cilia, one of them an abstract² of a paper of our own, could be misled by the accidents of context and wording into the belief that we are trying to use the internal structure of cilia as a basis for phyletic conclusions and that there is a fundamental difference between the green algæ in which Astbury and Saha¹ have found nine strands and all other plants in which there are eleven. To prevent such a mistake, it will perhaps be helpful to point out that the structure of the ciliary axis in all groups of plants and animals in which accurate work has been done appears to be identical. There is a precise and predetermined fibrillar structure composed of nine peripheral strands and a central pair (making eleven strands in all); there is also a superficial skin, some other components within the fibrils, and in certain cases at least there is a spiral winding between the peripheral fibrils and the core.