SOLEN. 241 



how carefully the great philosopher studied razor-fishes, 

 and with what interest he watched their doings and 

 chronicled their fears. 



In more modern times, about the commencement of the 

 last century, they had equal attraction for Eeaumur, who, 

 as we shall have occasion to shew presently, observed their 

 habits with like interest and care. The razor-fishes, how- 

 ever, would scarcely have attracted such attention had it 

 not been for their excellent qualities as articles of food. 

 They are among the most delicious of shell-fish when 

 properly cooked — broiling is the best method — and are 

 eaten in many parts of Britain, as well as abroad. They 

 bury in sand, mostly near low-water mark ; but many 

 species are only to be obtained by dredging, and some of 

 the smaller kinds live at very great depths. The valves 

 of the shell, being connected by epidermis, serve at once 

 as a protection and as a lining to their holes. Their pow- 

 erful foot, with its broad, finger-like extremity, enables 

 them to sink in sand or mud with great rapidity. It is 

 curious that Pliny, and after him Rondeletius, distinguished 

 between male and female Salens, — in their cases a distinction 

 probably fanciful, but worthy of note as a blind anticipa- 

 tion of the later discovery of the bisexuality of Acephalous 

 Mollusca. 



The Salens are remarkable for presenting the greatest 

 length and least breadth of all the bivalves. 



We find traces of this genus in shells presenting a close 

 similarity of external form among palaeozoic fossils. Not 

 until we reach the tertiary epoch do we find remains of 

 species very distinctly allied to such as now live. In 

 beds of the pleistocene epoch they become comparatively 

 abundant, but the genus must be considered rather as 

 belonging to the present than to any former period. The 



VOL. I. II 



