No. 15. ANOMIA. 



Antique Lamp. 



Of this peculiar genus of bivalves there are thirty species, many of which are 

 extremely rare and valuable. The Anomia differ materially in form ; some 

 resemble the shape of an oyster, others again are imperforated, and nearly or- 

 bicular, as the A. Placentia, and some are oblong, as the A. Bifida, &c. Many 

 species, particularly the A. Caput Serpentis, when seen in profile, resemble 

 the form of an antique lamp ; and a few, as the A. Psittacea, &c. are very sim- 

 ilar to the hooked or curved beak of a parrot. 



Animal aciliated, strap-shaped body, with bristles or fins affixed to the up- 

 per valve. Arms two, linear, longer than the body, convenient, projecting, 

 alternate on the valve, and ciliated each side ; the fringe affixed to each valve. 

 Shell inequivalve, one flattish the other gibbous at the base, with the beak pro- 

 duced and generally curved over the hinge ; one of the valves often per- 

 forated near the base hinge, with a linear prominent cicatrix, and a lateral 

 tooth placed within, but in the flat valve, on the very margin. Two bony 

 rings for the base of the animal. Many of this genus are only found fossil, 

 and therefore it is not reasonable to imagine, that we shall ever know the an- 

 imals by which they were inhabited. It is remarked by Dr. Pulteney, that 

 the animal of the Anomia is different from any other shell fish, and is not re- 

 ducible to any of those in a moluscus state hitherto known. Hence probably 

 the name Linnaeus imposed upon it, Anomia, [%\6ixi%) quasi irregularis dis 

 misclis a lege discrepans. The animal of the Anomia Cepa is figured by Mur- 

 ray in his " Fundamenta Testaceologia," torn. 2, page 23 ; and that of Anomia 

 Tridentata, by Forskael, in his " Icones Animalium," t. 6. 40 B. The dissim- 

 ilarity of the two, renders it highly probable, that in the different shells which 

 come under the appellations, the inhabiting animal is various. In the Anomia 

 Tridentata the animal is furnished with two flat, wedge-shaped, trilotated arms, 

 placed opposite to each other ; these it protrudes out of the shell, when it 

 moves, and they are the organs by means of which it swims in the sea. Some 

 other kinds have, instead of arms or the above-mentioned wedge-shaped or- 

 gans, only a ligament passing through the perforations of the shell, by means 



