PIIOLADIDEA. 123 



sented equally by British and exotic species. The 

 remarkable cup-shaped appendage surrounding the base of 

 the united siphons may be regarded as a rudimentary tube 

 for their protection— especially for the protection of the 

 complicated cirrhigerous disk which surrounds the openings 

 of the branchial and anal siphons in Pholadidece, and which 

 is so characteristic of them. M. Deshayes regards this 

 group as intermediate between PJiolas and Teredina, whilst 

 the latter is intermediate between Pholadidea and Teredo.^ 

 In some respects, however, the passage seems rather from 

 PJtolas towards Gastrochana and its allies, and in such a 

 position we have placed it here. 



P. PAPYRACEA, Solander. 



Plate V. Figs. 3, 4, 5, 6, and Plate 11. Fig. 1, and (animal) Plate F. f. 4. 



Pholas papyracea, Turt. Dithyr. Brit. p. 2, pi, ], f. 1 to 4.— Brown, 111. 

 Conch. G. B. p. 114, pi. 49, f. 4, 6, 7, 9. — Brit. Marine 

 Conch, p. 29. — Sowerb. Gen. Shells. Pholas, f. 3. — 

 Reeve, Conch. System, pi. 24, f. 3. — Ma we. Conch, 

 pi. 3, f. 5. — Sow. Conch. Man. f. bG. — Hanl. Recent 

 Sh. p. 9, sup. pi. 1. Phol. f. 1, 3. — Ind. Testae, sup. pi. 

 1. Phol. f. 1. 

 „ Lcanellata, Turt. Dithyr. Brit. p. 4, pi. 1, f. 5, 6.— Flem. Br. Anim. p. 

 456. — Brown, 111. Conch. G. B. p. 114, pi. 49, f. 10, 11. 

 —Ind. Testae, sup. pi. 1. Phol. f. 3. 

 Pholadidea Loscontliana, Turt. Conch. Diet. p. 147. 

 Pholas (Pholadidea) Goodallii, Diet. Sc. Nat. vol. xxxvii. p. 532. 



„ striata, Cuv. Anim. King. (edit. Griffith) pi. 8, f. 1.— Cuv. Anim. King. 

 (Henderson's edit.) pi. 41. f. 1. 

 Pholadc strite, Blainv. Manuel Malacol, pi. 80 his, f. 7. 



This delicate and remarkable shell, whose different 

 aspects in its mature and undeveloped state, have caused 

 so much controversy among English conchologists, is of 

 an elongated ovate shape, ventricose, very thin, not glossy, 



* Traite Elementairc do Conchyliologie, p. 75. 



