

BIOLOGICAL CLASSIFICATION. 1417 



Family TRIMERELLID^J Davidson and King. 



Dinobolus Hall, Monomorella Billings, Rhinobolus Hall, Trimereila Billings. 

 Superfamily LINGULACEA. 

 Family LINGULID^E Gray. 



Lingula Bruguiere (subgenera, Palseoglossa Cockerell, Pseudolingula Mickwitz), 

 Tunaria, Pizarroa and Bistramia Hoek (described as asymmetrical Lingulae, but 

 probably pelecypods). 



Family LINGULASMATID^E Winchell and Schuchert. 

 Lingulasma Ulrich, Lingulops Hall. 



Order NEOTREMATA. 



Superfamily SIPHONOTRETACEA. 

 Family SIPHONOTRETID^ Kutorga. 

 Schizambon Walcott, Siphonotreta Verneuil. 



Superfamily ACROTRETACEA. 



Family ACROTRETID^E Schuchert. 



Acrothele Linnarsson, Acrotreta Kutorga, Conotreta Walcott, Linnarssonella Walcott. 



Superfamily DISCINACEA. 

 Family TREMATID^E Schuchert. 

 Eunoa Clarke, Schizocrania Hall and Whitfield, Trematis Sharpe. 



Family DISCINID^ Gray. 

 Orbiculoidea D'Orbigny, Schizotreta Kutorga. 



Superfamily CRANIACEA. 



Family CRANIID^S King. 

 Crania Retzius, Petrocrania Raymond, Pholidops Hall. 



Order PROTREMATA. 



Superfamily ORTHACEA. 

 Family BILLINGSELLED^E Schuchert. 



Billingsella Hall and Clarke, Eoorthis Walcott (subgenus Orusia Walcott), Protorthis 

 Hall and Clarke. 



Family ORTHID^E Woodward. 



Dalmanella Hall and Clarke, Hebertella Hall and Clarke (subgenus Eridorthis 

 Foerste), Orthis Dalman, Orthostrophia Hall (subgenus Schizoramma Foerste), 

 Platystrophia King, Plectorthis Hall and Clarke (subgenera Austin ella and Encu- 

 clodema Foerste). 



Family RHIPIDOMELLHWE Schuchert. 



Bilobites Linnaeus, Dinorthis Hall and Clarke (subgenera Plsesiomys Hall and Clarke, 

 Valcourea Raymond, Heterorthis Hall and Clarke, Pianodema Foerste, Rhipido- 

 mella (Ehlert, Schizophoria King). 



