SYSTEMATIC 

 ARRANGEMENT OF CONCHIFERA, 



CLASS XII. 

 CONCHIFEKA. 



ANIMALS without distinct head, covered on each side with 

 a lamina of mantle. Shells two, incumbent on mantle. Heart 

 aortic. Respiration branchial, with branchiae mostly lamellose, 

 running out near the margins of body on each side, covered by 

 mantle ; in some the mantle itself discharging the office of 

 branchise. Some hermaphrodite, others with sex distinct: all 

 aquatic. 



ORDER I. Palliobranchiata or Brachiopoda. 



Body depressed, covered with mantle, bilobed, open. Branchiae 

 grown to the mantle or not distinct from mantle. Heart double, 

 arterial. Two long arms convoluted in form of a spiral, armed 

 with cirri or cilia. Mouth simple at the base of arms. Shell 

 bivalve, affixed, sessile or petiolate, adhering to mantle by several 

 oblique muscles. 



Family I. Brachiopoda. Characters those of the order. 

 On this order and family may be compared : 



CUVIER Mem. sur T Animal de la Lingula, Ann. du Mus. i. 1802, 

 pp. 69 80, PL v. reprinted in his Memoires sur VHist. et PAnat. 

 des Mollusq. No. 21. 



BRODERIP Descriptions of some new species of Brachiopoda, Trans. 

 Zool Soc. i. pp. 141 144. 



