BRAcHIOPODA. 897 
Zellania, Moore. 1854. 
Shells minute, subtriangular, impunctate. Hinge-line short, 
straight, with cardinal area on each valve. Foramen large, 
encroaching on the brachial valve. Median septum in each 
valve. In the brachial valve is a broad pustulose marginal area, 
Fics 639, 640. Zellania Davidsoni, Moore. (Davips0n.) 
the inner edge of which is thickened into a ridge, bilobed by the 
median septum. 
Type, Zellania Davidsont, Moore. 
Distribution.  Lias. 
Gwynia, King. 1859. 
Shell thin, minute, biconvex, elongate-oval. Hinge-line short, 
nearly straight. Foramen large, with incomplete deltidial plates. 
Interior without septa or loop. Brachia forming an uninter- 
Frias. 641, 642, Gwynia capsula, Jeffreys (sp.). (DAvIDsoN.) 
rupted circlet, the anterior cirri of which are but slightly 
developed. 
Type, Gwynia capsula, Jeffreys (sp.). 
Distribution. Recent (Lusitanian Province). 
Thecidea, Defrance. 1822. 
Synonym; Zhecidium, Sowerby. 1824. 
Shells plano-convex, elongate-oval; surface covered with 
radiating rows of granules. Pedicle-valve with elevated beak, 
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