340 GINGLYMACONCHA. AVICULIDZ. 
It is not uncommon on the western coasts of Cornwall, De- 
yonshire and Dorsetshire, and on the southern coasts of Ire- 
land ; at Yawl, Cork Harbour; Bantry Bay and Dingle Bay ; 
in Scotland, Bute, Arran, and the Hebrides; Sandgate, Kent ; 
and at Hastings, Sussex. 
ORDER II. MONOMYA. 
FAMILY If. AVICULIDZ. 
Shells equivalve, their hinge straight. 
The animal with its foot elongated, somewhat conical, with 
a byssus at its base. 
Genus 68. AvICULA. 
Avicula, D’ Argenville, Lamarck, Cuvier, &c. 
Teste ineequivalves, fragiles, submutice, aspectu’ superiore 
transverso recto extremitatibus productis ; antica caudiformi. 
Valva sinistra emarginata. Cardo linearis unidentatus ; dente 
im utraque valvA infra umbones. Ligamenti area marginalis 
angusta canaliculata, bysso non intersepta. 
1. AvicuLa BRITANNICA. 
Shells very smooth, shining chestnut, spotted with fuscous, 
and obliquely streaked with white lines; the anterior lobe 
wrinkled, the hinder one semicircularly striolated ; internally 
shining, silvery white. Length one meh; height half of an 
inch. 
Mytilus Hirundo, Linn. Lud. Ulr. 549. no. 140; Syst. Nat. 
1159; Gmel. Syst. Nat. 3357 ; Dill. Dese. Cat. 320; Turt. 
Conch. Dict. 108. 
Inhabits the deep sea on the coasts of Ireland and Devon, 
where it is very rare; but very common in the Mediterranean 
and Adriatic seas. 
