370 MACTRID^>. 



Mactrida, though with considerable hesitation, and only as 

 an arrangement for convenience. 



The shell of Lutrarla 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 Lutrarirc. are 

 recorded in lists of fossils, but their affinities with existing 

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

 ellfpfica, 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- 

 Jogical change which have disturbed them, even to the 

 present time. 



L. ELLiPTicA, Lamarck. 

 Somewliat elliptic, not at all arcuated. 



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



Macira Ivtraria, Linn. Syst. Nat. ed. 12, p. 1I2G. — Penn. Brit. Zool. ed. 4, 



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



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



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



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



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



— DiLLW. Recent Shells, p. 146. 



Lutraria eUijiiica, Lam. Anim. s. Vert. (ed. Desh.), vol. vi. p. 90. — Turt. Dithjr. 



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



Conch. G. B. p. 109, pi. 43, f. 2, 3. — Macgil. Moll. 



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



ii. p. 7. — Hanl. Recent Shells, p. 26 Ciienu, 111. Conch. 



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

 33, 35, 36 (animal). 

 „ vvl(jaris, Flem, Brit. Anim. p. 464. 

 Lutraire elliptique, Ciienu, Traits Elem. p. 170, f. 52 (hinge). 

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



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

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



