PLATE XXXI. 



The cost of this plate has been defrayed by the Carnegie Trust for the Universities 



of Scotland.) 



Fig. 



1. BothHolepis cristata, removed from the matrix, dorsal view. For explanation 



of lettering see restored outline of B. Canadensis on p. 112. Rosebrae 

 Quarry, Elgin, in the Elgin Museum. 



2. The same specimen replaced in the matrix and seen from the right side, the 



impression of the median crest being seen at G. 



3. Impression of the ventral surface of the same specimen, showing the pectoral 



appendages, which, however, are imperfect. 



4. Fragment of an impression of the dorsal aspect of Bothriolepis cristata, showing 



the deep narrow slit left by the median dorsal crest. From Rosebrae, in 

 the Royal Scottish Museum, to which it was presented by William Taylor, 

 Esq., Lhanbryde. 



All the figures on this plate are of the natural size. 



