80 



^ Fam. PKODUCTIDiE. 



Productus, Sowerby. 



Froducta, Sowerby, jr. 



ProduGta, M'Coy. 



Protonia, Link. 



* Pyxis, Chemnitz. 



Ariusculites, Murray. 



ArbusctiUthes, Paetel. 

 Chonetes, Fischer. 



Leptaena, M'Coy. 



Clionetus, Paetel. 

 Protluctella, Hall. 

 Strophalosia, King. 



Stropholosia, Gray. 



Stojyiialosia, Bronn. 



Lej)taenalosia, King. 



Orthoihrix, Geiuitz. 



Onfhotlrnx, Davidson. 



Orthotrix, auct. 

 Aulosteges, Helmersen, 



LYOPOMATA. 



Fam. Sll'HONOTRETIDiE. 



Siphonotreta, Verneuil. 



Siphonoirema, Dana. 

 Mesotreta, Kntorga. 

 Acrotreta, Kutorga. 

 Volborthia, Moller. 

 ? Eichwaldia, Billings. 

 ? Iphidea, Billings. 



Fam. Tr.iMERELLiD^. 



Trimerella, Billings. 



Trimecella, Paetel. 



Gotlandia, Dall. 



Rlujnobohis, Hall. 



Oboldlina, Billings. 

 Dinobolus, Hall. 



UngulUes, Queustedt. 



Conradia, Hall. 

 Monomerella, Billings. 

 ? Lingnlops, Hall. 



Fam. Obolidje. 

 Helmersenia, Pander. 

 Keyserlingia, Pander. 

 ? Kutorgina, Billings (pars). 



Kortugina, Davidson. 

 Monobolina, Salter. 

 Obolella, Billings. 

 ? Spondylobolus, M'Coy. 



Spondylobus, Davidson. 

 Aulonotreta, Kutorga (pars). 



Leptobolus, Hall. 



Leptohulns, Hall. 



Acritis, Volborth. 



Aerites, Dav. & King. 

 Obolus, Eichwald. 



Obulus, Queustedt. 



Ungiila, Pander. 



Ungulites, Bronn. 



Aulonotreta, sp. Kutorga. 

 (?) Schuiidtia, Volborth, not Bals.-Criv. 



Dicellomus, Hall. 



Fam. LiNGULiD^. 



Dignomia, Hall. 

 Lingulella, Salter. 

 Lingulepis, Hall. 

 Glottidia, Dall. 

 Glossina, Phillips. 

 Lingula, Brugifere. 



Ligula, Cuvier. 



Ligularius, Dumeril. 



Lingularius, Herrmannsen. 



Pharetra, Bolten. 



Fam. DiscmiD^. 



Discina, Lamarck. 



Orhicula, Sowerby. 

 Discinisca, Dall. 

 Trematis, Sharpe. 



Orbieella, D'Orbigny. 

 Orbiculoidea, D'Orbigny. 



ScMzotreta, Kutorga. 



Shizoireta, Davidson. 

 Schizocrania, Hall & Whitfield. 



Fam. CRANiiDiE. 



Crania, Eetzius. 



* Criopoderma, Poll. 



* Criopiderma, Poli. 

 Criopododerma, Agassiz. 

 Criopus, Gray. 



Cry opus, Deshayes. 



Craniolltes, Schlotheim. 



Crauiolithes, auctt. 



Discina, Turton. 



*Niimmulus, Waller. 



Numulus, Agassiz. 



Orbicula, Cuvier. 



Orbicularius, Dumeril. 

 Craniscus, Dall. 

 Ancistrocrania, Dall. 



Cranopsis, Dall, not Adams. 

 Pseudocrania, M'Coy. 



Craniops, Hall. 



Pholidops, Hall. 



Palwocrania, Queustedt. 

 Choniopora, Scbauroth. 



