112 NEW YORK STATE MUSEUM 



Devonian — Triassic Solenopsis, Pleurophorus 



Devonian — Cretaceous Pseudomonotis 



Devonian — Tertiary Parallelodon (maximum in Coal measures) 



Devonian — Recent Modiolus, Pteria 1 



Carboniferous — Cretaceous. Entolium, Myoeoncha 



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



Jurassic-Recent), Ostrea, Solemya, 



'■' r [^ Lithophagus (Lithodomus) 



Triassic — Cretaceous Homomya, Opis, Pleuromya, Tancredia, 



Unicardium 



Triassic — Tertiary Gervillia 



Triassic — 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 



Cretaceous — 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. 116) 



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, 



Scalites (?) 

 Silurian — Triassic Straparollus 



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

 Triassic-Cretaceous. 



