"Rhynchonella psittacea. Interior of doral valve. s, sockets; b, dental plates; V, mouth; de, labial appendage in itsnatural position; d, appendage extended or unrolled." — Encyclopedia Britanica, 1893

Dorsal Valve

"Rhynchonella psittacea. Interior of doral valve. s, sockets; b, dental plates; V, mouth; de, labial…