CLASS I 



PELECYPODA 



439 



Grammysia Vern. (Sphenoynya Hall) (Fig. 650). Shell elongate-ovate, concen- 

 trically sculptured, witli a deej) luniüe ; cardinal niargin thickened, edentulous ; 

 siirface with several radial 

 grooves. Silurian and De- 

 voiiian. Protomya Hall ih! 

 similar l)ut without the 

 grooves. 



Leptodomus M'Coy, Sil- 

 urian ; Elymella, Glossites^ 

 Euthydesma, Paleanatina 



and (?) Tellinopsis Hall ; 

 Devonian. 



Gardiomorpha Koninck. " ^'■" '''''^" 



C^^Tn^ iiiflaforl hoaVc olrv^r^cf Grmnmysia hamükmeni<is Vem. Spirifer Sandstone (Lower Devonian) ; 

 UVai,^ mnatea, OeaKS almost Lahnstein, Nassau (after Sandberger). 



anterior, cons2:)icuous, ad- 



jacent, prosogyrous ; hinge line thin, arched. Silurian and Carboniferous. 



Isoculia M'Coy. Like the preceding, but with coarse concentric sculpture, 

 Carboniferous. 



Other Carboniferous genera are Broeckia Koninck ; Ghaenomya Meek ; Sedgwickia 

 M'Coy ; and Edmondia Koninck. The last is like Gardiomorpha but gapes in front, 

 with a narrow ridge below the beaks. 



The Cambrian FordiUa Barrande, earliest of bivalves if a Mollusc, very likely belongs 

 to the bivalved Crustaceans near Estheria. It is minute, oval, somewhat arcuate, and eon- 

 centrically striated. Lower Cambrian ; New York and Massachusetts. 



Another bivalved shell, regarded by some authors as a Pelecypod, Modioloides priscus 

 Walcott, from the Lower Cambrian of eastern New York, is probably also of Crustacean 

 affinities. Pizzaroa, Tunaria and Bistramia Hoek, from' the Silurian of Bolivia, are probably 

 byssal bivalves. 



Family 5. Cardiolidae Neumayr. 



Shell equivalve, inflated, ohliquely ovate, with prominent heaks, and edentulous hinge ; 

 sculpture offen radial, or sometiraes of concentric ridges lohich may he confined to the 

 beaks. Silurian and Devonian. 



Gardiola Brod. (Fig. 651); Gloria Barrande; Eopteria 

 (? Euchasma) Billings ; from the Ordovician, may also belong here. 



Family 6, Antipleuridae Neumayr. 



Shell very inequivalve without gape below the beaks ; hinge 

 obscurely taxodont, with an amphidetic area and predominantly 

 radial sculpture. Silurian. 



Äntipleura, Dualina and Dalila of Barrande. 



Fig. 651. 



Cardiola cornucopiae 

 Goldf. Devonian ; Ebers- 

 reuth, Fichtelgebirge, i/^. 



Family 7. Praecardiidae Neumayr. 



Shell equivalve with taxodont dentition and usually strong 

 radial sculpture. Silurian and Devonian. 



This family contains the following genera of Barrande from the Silurian of 

 Bohemia : Praecardium, Paracardium, Puella, Pentata, Buchiola {Glyptocardia Hall), 

 Praelucina, Regina, Praelima ; to which Neumayr adds Pleurodonta Conrath, and 

 Pararca Hall. It is possible that Silurina Barrande, regarded by Neumayr as the 

 type of a distinct family, may also be included. It is distinguished by its feebler 

 structure and a dorsal radial groove near the cardinal border. 



