Goriuln.\ PELECYPODA. lOOi 



Fam. CORBULID^, Fleming. 



Animal with the siphons short, united, naked, and wholly retractile. 

 Dioecious. 



Shell small, subtrigonal, inequivalve, the left valve less convex 

 than the right ; pallial line feeble or obsolete ; the ligament usually 

 subexternal, separated from the resilium, which is internal, transverse 

 (alivincular), and extending on both sides of the beaks (amphidetic) ; 

 the chondrophore is received into a socket of the opposite valve, not 

 verged with the valve-margin ; hinge with 1 or 2 subumbonal pro- 

 jecting teeth, and rarely obscure traces of laterals ; posterior gape 

 inconspicuous. 



Trias to Recent. 



Genus 1. CORBULA (Bruguiere), Lamarck, 1799. 



Corbula, Bruguiere, Encycl. Meth., 1797, 230 ; Lamarck, Prodr., 1799, 89. 

 Type : C. gattica, Lamarck. Aloidis, Muehlfeldt, 1811. Lentidium, 

 C. & J., 1832. Erodona, Daudin, 1800. Azara, d'Orbigny, 1839. Pota- 

 momya, Sowerby, 1835. Corbulamya, Nyst, 1846. Erodina, Gray, 1847. 

 Pachydon, Gabb, 1868. Agina, Gray, 1847. Anisothyris, Conrad, 1870. 

 Anisorhynchus, Meek, 1872. Cuneocorbnla, Cossmann, 1886. Bothro- 

 corbula, Gabb, 1872. Bicorbula, Fischer. 1887. Not Corbnla. Bolten, 

 1798. 



Shell having the valves unequal, the right usually larger, both 

 more or less rostrate ; right valve with a single large tooth below the 

 beak, with a deep resiliary pit behind it, and no lateral laminae ; the 

 left valve without laterals, with a more or less prominent process upon 

 which the resilium and ligament are inserted, in front of a socket 

 into which the cardinal tooth of the right valve fits ; the posterior 

 margin of this socket is sometimes elevated like an indistinct tooth ; 

 beaks prominent, prosogyrate or erect, the right one usually superior 

 to the left ; sculpture variable ; often discrepant on the 2 valves, 

 rarely reticulate, and never strongly radial ; pallial line with a small 

 sinus, or none ; lunule and escutcheon usually absent ; ligament 

 chiefly internal. 



Distribution. Europe, United States of America, west Africa, 

 China, Australasia, &c. Chiefly marine. 



Fossil. Secondary and Tertiary. 

 Vernacular Name. Basket-shell. 



KEY TO SECTIONS. 



A. Right valve with a cardinal tooth below the beak. 



a. Without keels^on the rostrum . . . . . . CORBULA, a. str. 



b. Rostrum keeled . . . . . . . . . . ALOIDIS. 



B. Right valve with a deep pit for the resilium, hinge-plate 



turned up on each side of the pit, but no distinct 



cardinal tooth . . . . ERODONA 



