OSTRACEA. MOLLUSCA. ANOMIA. 139 



Trans., viii. 102. Donovan; Brit. Shells, i. \,^\.2Q>. Born; Mus., p. 117. 

 ScHROET.; Einl. in Conch., iii. 383. Pen; Test., ii. 186, pi. 30, f. 9, 11. 

 Da Costa; Brit. Conc/t., 1G5, pi. 11, f. 3. Favanne ; CoMc/t.,pl. 41, f. B. Dii.l- 

 wyn; Catal., i. 286, No. 3. Blainv. ; Malacol., pi. 5LI, f. 3. SovvEKiiy ; 

 Genera, f. 1, 2, 3. Turtojv ; Brit. Biv., 227. Conch. Diet., 2. Lam.; An. 

 sans Vert., vii. 273. Fleming ; Brit. Jlnirh., 395. 



Shell generally rounded, but often produced at one side or at 

 base so as to assume an oval form ; its margins more or less 

 jagged, and its surface scaly from the loose edges of the lines of 

 growth, and variously distorted, undulated, and plaited, according 

 to the objects to which it adheres. Lower valve flat, its aperture 

 ovate, reaching the margin by a fissure. Upper valve slightly 

 convex, little elevated about the beak, which is small, acute, not 

 quite reaching the margin. Substance of the shell pearly, or like 

 talc, of a greenish tinge, reflecting golden and silvery hues ; within 

 smooth, the muscular impressions opake white. Usually about 

 an inch in diameter, but growing to three times that size. 



It is found in abundance in oyster beds, adhering to oysters. 

 At New Bedford it has been found anchored by its muscle to 

 pebbles. 



This shell varies so much in its form, that it is very difficult to 

 characterize it. The most constant trait is the rugged, scaly exterior. 

 It not unfrequently assumes a ribbed appearance, in consequence of 

 having adhered to valves of Pecten concentricus. 



Anomia aculea'ta. 



Shell rounded^ inclined to be straight at the hinge margin ; 

 color dingy-white ; beaks obtuse, terminal ; upper valve covered 

 with fine, prickly, radiating lines ; lower valve smooth ; aperture 

 circular. 



Figure 90. 



State Coll., No. 147. Soc. Cab., No. 2347. 



Anomia aculeata, Gmehn ; Syst.fd^iG. Turton ; Lin. Syst., iv. 285. Brit. Biv., 

 233. Conch. Diet., 4 Chemn. ; Conch., viii. 92, t. 77, f. 702. Montagu; 

 Test. Brit., 157, 1.4, f. 5. Pennant; Brit. ZooL, iv. 233. Dillwvn; Catal., 

 288. Maton and Rackett ; Lin. Trans., viii. 103. Wood ; Index, pi. 11, f. 3. 



Shell small, rounded, the hinge margin more or less truncated 

 or straight, color yellowish-white ; upper valve convex, the beak 



