Saxicava. Bores and inhabits stone. 

 Fig- . 



15. S. rugosa, Zwm. — Mytilus r., Hiatella r., S. gallicana, 5. pholadis, 



Byssomya pholadis, My a byssifera. — Eng., Scot., Ire., C. Valves 

 oval. 



16. S. arctica, Linn.- — {My a) Hiatella a., Anatina a., Hiatella minuta, 



Solen minutus, S. rkomboides, Agina purpurea, Solen p. — Eng., 

 Scot., Ire., C. Valves rhomboidal ; angle serrated. 

 Omitted. — S. fragilis, Nyst. Not the young of S. rugosa. Vigo Bay. 



Petricola. Inhabits stone. 



17. P. lithophaga, Retz. — P. striata, costellata, rocellaria, ruperella, 



Lamk., My a and Spkania decussata. — Cork, Bristol, R. as British. 



Venerupis. Bores and inhabits stone. 



18. V. Irtjs, Linn. (Donax). — Tellina cornubiensis, Cuneus foliaceus, 



Pelric, and Pullastra, I. — In limestone at Plymouth and other 

 southern coasts. Wedge-shaped. 



Mya. Burrows in mud and sand. 



19. M. truncata, Linn. — M. ovalis and Spkania Swainsoni (young). 



— Various localities and depths, C. Truncated at end. 



20. M. arenaria, Linn. — Heme Bay, Portsmouth, etc., C. Tapering 



at end. 



PanopjEa. Burrows in mud. 



21. P. norvegica, Spengl. — P. glycimeris, P. arctica. — Scarborough, 



Zetland (90 fath.), Rr. Quadrate. 

 21*. P. ALDROVANDi,2/a»2/£. — Corn wall, one specimen, Jeffreys. Oblique. 



Corbula. Dredged in mud and sand. 



22. C. nucleus, Lamk. — C. striata, Mya, and C. inaquivalvis. — Dublin, 



Torquay, Forth, 4 to 80 fath., C. Valves unequal, beaked. 



23. C. rosea, Brown. — Weymouth, Er. as Brit. Valves not beaked. 



24. C. ovata, Forbes. — Isle of Man, Rr. Oval, truncated at end. 



Sph^enia. Burrows in foliaceous shells. 



25. S. Binghami, Turt. — Corbula B. — Torquay, Guernsey, Swansea, 



Forth, etc., R. 



NejERA. Lives incrusted in sand. 



26. N. costellata, Desk. — Corbula c. N. sulcata. — Loch Eyne, Rr. 



Radiately 3-ribbed. 



27. N. cuspjdata, Olivi. — Forth, Northumberland, Cape Clear, etc., 



Mr. Pear-shaped. 



28. N. abbiieviata, Forbes. — Loch Fyne, Mc. Radiately 1-ribbed. 



031 



