144 DIMYAIRA. 



and from the Saxicava by the ligament being placed on the shortest side of 

 the shell. 



Glycimeris siliqua.—'TiiE PoD Glycimeris. Plate XVIII. 

 fig. 7. Transversely oblong ; covered with a black epidermis ; 

 umbones decorticated ; internal disc of the valves white^, callous, 

 and thick. Two inches and a half broad. Inhabits the North 



Genus 65— PAN OPE A.— Zamarc/^. 



Generic Character. — Equivalve, transverse, gaping unequally 

 at the sides ; one conical primary tooth in one valve, and a com- 

 pressed, short, ascending callosity on each side ; ligament exter- 

 nal, affixed on the elongated side of the shell, over the callosi- 

 ties. 



The more prominent apices of the shells of this genus at once distinguish 

 them from the Myae. 



Panopea Aldrovandi. — Aldrovandus's Panopea. Plate 

 XVIII. fig. 8. and 9. Transversely elongated, undulated; 

 concentrically wrinkled ; of a yellow-fawn colour. Inhabits the 

 Mediterranean. 



Genus 66. — SOLE N.—ZinwiPMs. 



Generic Character. — Equivalve, transversely elongated, gap- 

 ing at both extremities ; beaks very small, always short ; pri- 

 mary teeth small, varying in number, sometimes none, and rare- 

 ly a pit between them ; ligament external. 



There are three sections in this genua : — * Shells with a terminal hinge ; 

 and anteriorly truncated. ** Primary teeth somewhat distinct from the an- 

 terior margin. *** Hinge situated nearer the middle than the anterior 

 end. 



Solen Ensis.— Tn^ Sabre Solen. Plate XVIII. fig. 11. 

 Linear, sabre-shaped, somewhat reflected at the end next the 

 hinge ; in each valve a single compressed tooth without laminae ; 

 olive-brown towards the base of the shell, and next the apex 

 brownish-purple. From five to seven inches broad. Inhabits 

 the seas of Europe. 



