MOD I OLA. 55 



Indiana,' pp. 701 — 704, pi. xx, figs. 1 — 10, S. A.Miller describes and figures from 

 Carboniferous beds — 



Schisodus Harii, n. sp. 

 Cypricardella Qorlyi, n. sp. 

 Aviculopecten seulptilis, n. sp. 



Pterinopecten Sedaliensis, n. sp. 

 Grammy sia Blairi, n. sp. 

 Conocardium Indianense, n. sp. 



DESCRIPTION OF SPECIES. 

 Family MYTILID^. 



Shells elongate, wedge-shaped, narrow, and tumid anteriorly, expanded and 

 flattened posteriorly. Pallial impression entire. Adductor muscle-scars two or 

 more in each valve. 



Observations. — The family Mytilidse were well represented in palseozoic times, 

 several well-defined genera having already come into existence. 



M'Coy, ' British Pal. Fossils,' p. 265, classed together a number of genera 

 under the family MytilidaB, which have not, however, been generally recognised 

 as having much affinity by subsequent investigators. For instance, his family 

 Mytilidae includes Mytilus, Lithodomus, Modiolopsis, Dreisena, Hippopodium, 

 Pinna, Dolabra, Myaphoria, Anodontopsis, Lyrodesma (Actinodonta), Clidophorus, 

 Tellinomya, Orthonotus, and apparently (p. 499) Edmondia. This very hetero- 

 geneous group cannot be retained. The same author refers the genus Myalina 

 with Ambonychia to the Aviculidge, and this classification is accepted by many, 

 but I advance reasons for placing these two genera in the Mytilidse, though in 

 certain characters they have a slight afiinity with the Aviculidse. 



Genus Modiola, Lamarck, 1801. 

 List of the synonyms in writings of vafious authors on Carboniferous Mollusca. 



iSon Modiola, Fleming, 1825. Edinb. Phil. Journ., vol. xii, p. 246. 



— — Fhillips, 18S6. Geol. of Yorkshire, vol. ii, p. 209. 



— — pars, Sowerhy, 1840. Trans. Geol. Soc, ser. 2, vol. v, p. 491. 



— Portlock, 1843. Eeport Geology Loudouderry, p. 424. 



— pars, Morris, 1843. Catal. Brit. Foss., p. 81 ; 1854, p. 209. 



— M^Coy, 1844. Synopsis of Carboniferous Fossils of Ireland, p. 74. 



— pars. Brown, 1849. lUustr. Fossil Conch. Great Britain, p. 173. 

 Mytilus, pars, de Byckholt, 1847. Melanges paleontologiques, pt. 1, p. 132 ; 1853, 



pt. 2, p. 87. 



