112 ■ ■ NEW YORK STATE MUSEUM 



Devonian — Triassic Solenopsis, Pleurophorus 



Devonian — Cretaceous .^Pseudomonotis 



Devonian — Tertiary Parallelodon (maximum in Coal measures) 



Devonian — Recent Modiolus, Pteria^ 



Carboniferous — Cretaceous, Entolium, Myoconcha 



Carboniferous — Recent Atrina, Lima (subgenera: subgenus Limaea: 



Jurassic-Recent), Ostrea, Solemya, 



' .' |^i_£ Lithophagus (Lithodomus) 



Triassic — Cretaceous Homomya, Opis, Pleuromya, Tancredia, 



Unicardium 



Triassic — Tertiary Gervillia 



TriaS'sic — Recent Alectryonia, Cardita, Cardium (subgenera), 



Chlamys, Corbula, Gastrochaena, Hinnites, 

 Limopsis, Mytilus, Pedalion (Perna auct.), 

 Plicatula, Thracia, Lucina 



Jurassic — Tertiary Anisocardia, Gryphaea 



Jurassic — Recent Amusium, Anatina, Anomia, Arctica, Camp- 



tonectes, Corbis, Cucullaea, Cuspidaria, 

 Cyrena, Cyrtopinna, Isocardia, Phola- 

 domya, Pholas, Pinna, Spondylus, Tellina, 

 ' Teredo, Trapezium, • Venus, Trigonia 



Cretaceo'us — Recent Acila, Acharax, Yoldia, Batissa, Chama, 



Clavagella, Crassatellites, Dosinia, Gly- 

 cimeris, Panope, Pecten, Pseudamusium, 

 Sphaerium, Spisula, Venericardia, Ungulina, 

 Thyasira, Paphia 



Among the Scaphopoda the persistent types are represented by : 



Silurian (?) — Recent Laevidentalium 



Carboniferous — Triassic .... Plagioglypta 



Cretaceous — Recent Antalis, Fustiaria, Cadulus 



The Gastropoda furnish the following persistent genera : 



Cambrian — Silurian Trochonema 



Cambrian — Carboniferous . Subulites 



Cambrian — Triassic Murchisonia 



Cambrian — Recent! Capulus (see p. ii6) 



Ordovician — Devonian Cyclonema, Eunema, Holopea, Lophospira, 



Oxydiscus, Sinuites 

 Ordovician — Carboniferous . .Omphalotrochus 

 Silurian, — Carboniferous Diaphorostoma, Lepetopsis, Metoptoma, Holo- 



pella, Natiria, Orthonychia, Platyceras, 

 ' ; ~^ Platyschisma 



Silurian — Permian Bellerophon 



Silurian — Triassic Euomphalus, Loxonema, Macrocheilus, 



Scalrtes (?) 

 Silurian — Triassic Straparollus 



^ Several subgenera, among them Meleagrina, Jurassic-Recent ; Oxytoma, 

 Triassic-Cretaceous. 



