ball: mactrid^ and mesodesmatid^. 211 



SYSTEMATIC TABLE OF THE GROUPS. 



Family MACTRID^. 



Subfamily MACTRm^. 



Genus Mactra (Linne), Lam., 1799. 

 Type. — M. stultorum, L. 



Subgenus Ccelomactra, Dall. Ty2)e. — M. violacea (Ch.), Gmelin. 



Subgenus Mactrodcrma, Dall, 1894. Ty2}e. — M. velata^ Phil. 



Section Itactroderma, s.s. M. relata, Phil. 

 Section Cyclomactra, Dall. M. trish's, Gray. 



Subgenus Madrotoma, Dall, 1894. Tyjye. — M.fragilis, Gmel. 



Section Simomactra, Dall. M. dolahriformis, Conr. 

 Section Micromactra, Dall. M. californica, Conr. 



Subgenus Mactrella (Gray), Dall, 1894. Type. — M. data, Spongier. 



Section Mactrella, s.s. M. alata. Spongier. 

 Section Harvella, Gray, 1853. M. elegans, Sby. 

 Section Madrinala, Gray, 1853. M. pUcataria, Lam. 



Genus Spisttla, Gray, 1838. 

 Type. — Mactra solida (L.), Gray, 1847. 



Subgenus Hemimactra, Swn., 1840. Type. — M. soUdissima, Dillwyn. 



Section Mactromeris, Conr., 1868. M. polynyma, Stm. 

 Section Pseudocardmm, Gabb, 1869. Miocene : Cardium 



Gabhi, Rem. 

 Section Oxyperas, Morch, 1853. M. triangularis. Lam. 



Subgenus Leptospisula, Dall, 1894. Type. — M. striatella, Lam. 



Subgenus Cymhophora, Gabb, 1869. Cretaceous. Type. — Mactra 



Ashhtirneri, Gabb, Cala. 



Subgenus Schizodesma, Gray, 1837. Type. — M. Spengleri, Linne. 



Genus Mclinia, Gray, 1831. 

 Type. — M. typica, Gray ( = edulis, King). 



Genus PcAngia, C. Des Moulins, 1832. 



l_Gnathodon, Gray, 1831, non Goklfuss, 1820 (Pisces). j 



Type. — R. cyrenoides, Desm. 



