Published online by Cambridge University Press: 06 July 2012
The general relationships of the caudal scales in Adpenser sturio and Acipenser ruthenus are considered together with a detailed description of the structure of the scales and corium in A. ruthenus, and a new staining method using purpurin counterstained with aniline blue for differentiating dermal structures in sections is described. A comparison of the caudal scales of sturgeons with those of palæoniscids indicates considerable agreement in form and arrangement between them. Evidence is presented to show that the caudal scales in sturgeons and palæoniscids are distinct from the general body covering of scales, and evidence points to a similar, though reduced, squamation in Lepidosteus and possibly in Polypterus. The importance of the caudal scales in protecting the internal organs in the epichordal lobe of the tail and the significance of the boundary between the body and caudal scales as a hinge for tail flexure is discussed.
This paper was assisted in publication by a grant from the Carnegie Trust for the Universities of Scotland.