Loc., fossil, Scottish and Irish glacial beds. In the mammaliferous crag at Bramerton.
Loc., living. Throughout the European Seas.
Note. Fossil in the coralline and red crags.
23. Saxicava rugosa (Mytilus sp.), Linnæus.
Syn., Hiatella rugosa, Fleming. Saxicava pholadis of Lamarck; Solen minutus of Linnæus; Hiatella oblonga of Turton; Hiatella arctica of Lamarck, and Mytilus præcisus of Montagu, are all varieties of this protean species. Agina purpurea of Turton appears to me to be a form of the young shell.
Loc., fossil. One of the most generally distributed shells in the glacial beds. It occurs in all the Irish, Scotch, and English fossiliferous drifts and glacial clays, including the Bridlington beds and the mammaliferous crag of Thorpe. Abroad it is found in the glacial formations of Scandinavia, Russia, and Canada.
Loc., living. In all the seas of Northern and Arctic Europe, Boreal America, and Greenland. It ranges as far south as the Canary Isles, (d'Orbigny). Its vertical range is very great. In the British Seas it is found abundantly in the laminarian and coralline regions. In the Mediterranean I have observed it alive at all depths between twenty and eighty fathoms.
Note. Saxicava rugosa appears in all its forms in the coralline, and afterwards in the red crag.
24. Saxicava sulcata, Smith.
Loc., fossil. In the Clyde, Swedish, and Canadian beds.
Loc., living. Is not this the Greenland Mga byssifera of Otho Fabricius? It is possibly only a variety of the last.
25. Psammobia feroensis (Tellina sp.), Gmelin.
Loc., fossil. In the Lancashire and Irish drift. Always rare.
Loc., living. In the beds of Northern and Celtic Europe, frequent Rare in the Mediterranean.
Note. Occurs in the coralline crags; also in the Campinian beds of Belgium, according to M. Nyst.
26. Donax trunculus, Linnæus.
Loc., fossil. In the Irish beds. In the mammaliferoua crag at Bramerton.
Loc., living. Throughout the Celtic and South European Seas, ranging to Senegal (Adamson). Phillippi mentions it among the Red Sea shells collected by Von Hemprich and Ehrenberg. It is always littoral.
Note. The earliest appearance of Donax trunculus in the British area dates from the epoch of the Mammaliferous Crag, It is among the species marked by Phillippi as very rare in the Sicilian tertiaries.
27. Tellina crassa. Gmelin.
Syn., Tellina obtusa, Sowerby (Min. Conch.). Arcopagia crassa, Browm
Loc., fossil. Mammaliferous crag at Portwick. Some fragments from the Irish beds appear to belong to this species.
