130 



SYNOPSIS OF AMERICAN FOSSIL BRACHIOPODA. 



[lui.L. 87. 



1. Family AOROTRETID^ Scliuchert, 1803. 

 Acrotretiicea witli the pedicle openinji jmsterior to the proteguluiu. 



Acrothele TJiiuarsson, 1870. 

 Liiiiuirssouia Walcott, 1885. 

 Discinopsis (Mattliew) Hall and 



Clarke, 1892. 

 Acrotreta Kutorga, 1848. 



Uouotreta Walcott, 1880. 

 ?Mesotreta Kntorga, 1848. 

 fOrbicella d'Orbigny, 1849. 



Keysorlingia Pander, 1K61. 

 MIeliiiersenia Pander, 1801. 



2. Family SIPHOKOTKETID.F: Kntorga, 1848. 



Acrotretacea AAnth the pedicle opening passing by resorption anteri 

 orly through the protegulnm and the umbo of the shell. 



Yorkia Walcott, 1897. 

 Trematobolus Matthew, 1893, 

 Siphonotreta de Verneuil, 1845. 



Protosiphon Matthew, 1897 



Schizambon Walcott, 1884. 



Scbizamboiiia ffihlert, 1887. 



Snperfamily DISCINACEA Waagen, 1885. 

 Daikaulia (jiartiiu) W:iaj;t'n, 1885; Diacaulia (partim) Hall and Clarke, 1895. 



Neotremata with phos[)hatic shells, alistrium, but with no deltidium. 

 Dorsal protegnlum usually subcentral. 



1. Family TREMATIDiE Schuchert, 1893. 



Primitive Discinacea, in which the posterior margin of the ventral 

 valve has a triangular pedicle notch throughont life. A listrium is usu- 

 ally present. 



Discinolepis Waagen, 1885. 

 Trematis Sharpe, 1847. 



Orbicella Hall and Whitfield, 1875 

 (not d'Orhiguy, 1849). 

 Schizocrania Hall and Whittield, 

 1875. 



Schizobolus Ulrich, 188(i. 

 Liugulodiscina Whittield, 1890. 

 CElilprtella Hall and Clarke, 1890. 

 ? Monobolina Salter, 1805. 



2. Family BISCIKIDyE Gray, 1840. 



Orbiculidrt- McCoy, 1844. 



Derived Discinacea with an oi)en pedicle notch in early life in the 

 posterior margin of the ventral valve, which is closed posteriorly dur 

 ing neanic growth, leaving a more or less long, narrow slit partially 

 closed by the listrium. 



Orbiculoidea d'Orbigny, 1847. 

 Schizotreta Kutorga, 1848. 

 Lindstrcemella Hall and Clarke, 



1890. 

 Ra*merella Hall and Clarke, 1890. 



Discina Lamarck, 1819. 



Orbicula Sowerby, 1830 (not Ciivier, 

 1798). 



Discinisca Dall, 1871. 



