370 MACTRIDiE. 



Mactrid^, tliongli with considerable hesitation) and only as 

 an arrangonicnt for convenience. 



The shell of Lutraria is found by Dr. Carpenter to be 

 composed of elongated fusiform cells, their extremities 

 cropping out, one set above another. The species of this 

 genus chiefly affect temperate seas. Many LutrarifE are 

 recorded in lists of fossils, but their affinities with existing 

 forms is doubtful. One of our native species, the Lutraria 

 ellijytica, which now ranges throughout the European seas, 

 anciently inhabited our area even so far back as the epoch 

 of the coralline crag, and has maintained its place near the 

 British shores throughout all the ups and downs of geo- 

 logical change which have disturbed them, even to the 

 present time. 



L. ELLiPTicA, Lamarck. 

 Somewhat elliptic, not at all arcuated. 



Plate XII ; and (animal) Plate II. fig. 2. 



Ma ctru lutraria, h\s-ii. Syst. Nat. ed. 12, p. 1126. — Penn. Brit. Zool. ed. 4, 

 vol. iv. p. 92, pi. 55, f. 44. — Pulteney, Ilutchins, Dorset 

 Hist. p. 32.— Dorset Catalog, p. 33, pi. 5, f. 11.— Mont. 

 Test. Brit. p. 99.— Dong v. Brit. Shells, vol. ii. pi. 58.— 

 Linn. Trans, vol. viii. p. 73. — Turt. Conch. Diction, p. 84. 

 — CiiEMN. Conch. Cab. vol. vi. p. 239, pi. 24, f. 240, 241. 

 — DiLLW. Recent Shells, p. 146. 

 Lutraria ellijitiai. Lam. Anim. s. Vert. (ed. Dash.), vol. vi. p. 90. — Turt. Dithyr. 

 Brit. p. 65. — Brit. Marine Conch, p. 45. — Brown, 111. 

 Conch. G. B. p. 10,0, pi. 43, f. 2, 3. — Macgil. Moll. 

 Aberd. p. 291. — Piiilippi, Moll. Sicil. vol. i. p. 9, and vol. 

 ii. p. 7. — Hanl. Recent Shells, p. 26. — Ciienu, III. Conch. 

 Lutr. pl. 1, f. 10. — Desh. Exp. Scient. Alger. Moll. pl. 

 33, 35, 36 (animal). 

 „ vulgaris, Flem. Brit. Anim. p. 464. 

 Luiraire elliptiquc, Chenu, Trait6 Elcm. p. 170, f. 52 (hinge). 

 List. Hist. Conch, pl. 415, f. 259.— Encycl. Meth. Vers, pl. 258, f.3. 



Of a produced elliptic form, the valves of this shell, 

 which may be reckoned one of our largest bivalves, are, 



