86 JOUENAL OF THE NEW JERSEY 



at the hinge, with the double margins pendent and fringed but 

 with no ocelli ; gills two on each side, unsymmetrical, united 

 posteriorly; foot small, cylindrical, expanded and grooved at 

 the end ; byssus large, scaly, passing through a hole in the man- 

 tle and attached by a powerful muscle to the left valve. 

 1. Anomia, L. 

 Shell suborbicular, thin, pearly, translucent, with a deep notch 

 or hole in the right valve for a plug which is used to fasten the 

 shell to other shells; this lower valve is flat or concave. Animal 

 with open mantle and small, cylindrical foot. 



1. Anomia simplex, Orb. (Fig. 1.) Shell orbicular or distorted ; 

 upper valve very convex, its umbo not reaching the edge, and 

 its surface very variable, its shape dependent upon the shell to 

 w4iich it adheres ; lower valve smaller, with a circular hole very 

 near the margin, often with the edge open. Polished black, red, 

 yellow, or ashy to white ; interior the same, except the nmscular 

 impression which is white. Diameters about 25. — Whole coast. 

 Common south. 



2. Anoniia aculeaia, L. Shell smaller than the preceeding, 

 and with the upper valve covered with fine, prickly scales ar- 

 ranged in radiating lines ; the umbo reaching the edge ; lower 

 valve smooth. Yellowish to whitish. Diameter about 12. — New 

 York and north. Common north. 



Family 3. PECTINID/E. 



Represented only by the genus : — 



1. Pecten, Mul. 



Shell suborbicular regular, resting on the right valve, usually 

 ornamented with radiating ribs; ambones approximate, eared, 

 making the hinge line straight; only one, very faint, muscular 

 impression ; anterior ear more prominent ; right valve with a 

 notch below the front ear ; ligament narrow ; internal cartilage 

 in a central pit. 



Animal with open mantle; the margins double, the inner 

 pendent, like a curtain, finely fringed ; at its base, a row of many , 

 bright, black eyes, surrounded by tentacular filaments; gills ex- 

 ceedingly delicate, crescent shaped ; foot finger like, grooved ; 

 one adductor muscle. These animals are very beautiful, and can 

 swim and skip over the sand and mud with great dexterity ; the 



