BIOLOGICAL CLASSIFICATION. 1417 



Family Trimerellhxe Davidson and King. 



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



Superfamily LINGULACEA. 



Family Lingulim: Gray. 



Lingnla Bruguiere (subgenera, Pakeoglossa Cockerel 1, Pseudolingula Mickwitz), 

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

 probably pelecypods). 



Family Lingulasmatid^e Winchell and Schuchert. 

 Lingulasma Ulrich, Lingulops Hall. 



Order Neotremata. 

 Superfamily SIPIIONOTRETACEA. 

 Family Siphonotrettd.e Kutorga. 

 Schizambon Walcott, Siphonotreta Verneuil. 



Superfamily ACROTRETACEA. 



Family Acrotretid;e Schuchert. 



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



Superfamily DISCINACEA. 



Family Trematid^ Schuchert. 



Eunoa Clarke, Schizomania Hall and Whitfield, Trematis Sharpe. 



Family Discinid^e Gray. 

 Orbiculoidea D'Orbigny, Schizotreta Kutorga. 



Superfamily CRANIACEA. 

 Family Craniid/E King. 

 Crania Retzius, Petrocrania Raymond, Pholidops Hall. 



Order Protremata. 



Superfamily ORTHACEA. 

 Family Billingsellid^: Schuchert. 



Billingsella Hall and Clarke, Eoorthis Walcott (.subgenus ( >i u.-ia Walcott), Protorthis 

 Hall and Clarke. 



Family OrthiD/E Woodward. 



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

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

 Platystrophia King, Plcctorthis Hall and Clarke (subgenera Auatinella and Encu- 

 clodema Foerste). 



Family Rhipidomellid/E Schuchert. 



Bilobites Linnaeus, Dinorthis Hall and Clarke (subgenera PUesiomys Hall and < larke, 

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

 mella (Ehlert, Schizophoria King). 



