History of British animals - University of Guam Marine Laboratory

396 MOLLUSCA. OSTREADiE. Anomia.Tart. Linn. iv. 288.— A. cymbiformis, Maton and liackett, Linn. Trans,viii. 104. t. iii. f. 6. Mont. Test. Brit. Sup. 64—A. cylin. Turt. Biv.Brit. 232—On fuci and sertularise.Length about half an inch, breadth a quarter, narroAver towards the beak,which curves over the under valve, and ends in an obtuse point ; sometimessmooth, but usually with some rough transverse marks, but no longitudinalones.396. A. striolata.— Shell oval, somewhat cylindricallyconvex,and striate longitudinally,with the beak curved backwards.Turt. Biv. Brit. 233—Roots of fuci.Resembles the last, but is marked with fine, rather remote, longitudinalraised lines.397. A. aculeata.— Shell orbicular, with numerous longitudinalprickly striae.Mont. Test. Brit. 157- t. iv. f. 5. Turt. Biv. Brit. 233—On fuci andamong rocks.Diameter about half an inch ; depressed, whitish prickles rounded above,;concave, and somewhat concentrically disposed by the lines of growth under;valve wrinkled concentrically ;seldom prickly.398. A. fornicata.— Shell somewhat orbicular, and finelystriate, the upper valve furnished with a vaulted chamber on theinside, under the beak.Lamk. Syst. vi. 228. Turt. Biv. Brit. 234. t. xviii. f. 12, 13—From Torbay,Dr Turton.Diameter about half an inch ; flat, white, margin sinuous ; longitudinalstriae towards the margin, and fine regular transverse ones towards the pointedbeak inside ; silvery under the ; hingeis a large vaulted chamber, which,on one side, is much curved, and scaly on the outside ; perforation of the undervalve round, and nearly closed.399. A. tubularis.—" Shell orbicular, with the perforation ofthe under valve entire, and forming a cylindrical tube.""Turt. Biv. Brit, ccxxxiv—On fuci.Shell about a quarter of an inch in diameter ; whitish, with the beak terminal;the under valve has the perforation entire all round, and producedinto a raised cylindrical tube ;the plug of attachment is tendinous."It is probable that several of the preceding shells may yet be reduced to therank of varieties. In the mean time, we have followed the arrangement ofDr Turton.EXTINCT SPECIES.1. A. lineata Suborbicular, convex; when old, contracted towards thebeak ; longitudinally striated ; perforation of the lower valve circumscribed.—Sower. Min. Conch, t. ccccxxv.—In London Clay.