4 PLKURONECTID.E. 



much similarity between the Smahvarf and the Sail fluke, 

 but none of the four specimens of the former, noticed by 

 Sundevall, have so many dorsal and anal rays as the 

 Orkney Fluke. In the latter, also, the upper eye is more 

 distinctly behind the lower one, and the mandible pro- 

 trudes farther. Sundevall makes no mention of trans- 

 parent cheeks ; for the present, therefore, they are de- 

 scribed as distinct, such a proceeding being less injurious 

 to science than the junction of two species divers in 

 structure and habits under one name. In the absence of 

 a specimen, the Sail-fluke is placed in the genus Zeugop- 

 terus interrogatively. A single row of jaw- teeth only is 

 mentioned by Dr. Duguid, but he probably means late- 

 rally, where the Smahvarf has only one row, though 

 there is a crowded patch at the symphyses of its jaws. 



SUGAR-LOAF, SUTHEKLANDSHIRE. 



