894 Report or THE STATE GEOLOGIST. 
tum; above their insertion arise the ascending processes which 
are broad, concave, triangular plates, with their apices tapering 
backward but not uniting. 
Fias. 628-626. Magas pumilus, Sowerby. (DAvIDsON.) 
Type, Magas pumilus, Sowerby. 
Distribution. Cretaceous. 
Rhynchora, Dalman. 1828. 
Shell elongate-ovate, coarsely plicate. Hinge-line short, 
straight. Foramen large, subcircular, deltidial plates wanting. 
Teeth, sockets and cardinal process well developed. A low 
median septum in each valve. Loop not known. 
Type, Rhynchora costata, Wahlenberg (sp.). 
Distribution. Cretaceous. 
Rhynchorina, (hlert. 1887. 
Shells small, transverse, the hinge line, which is straight, mak- 
ing the greatest diameter of the valves. Umbones very depressed. 
Surface smooth. Teeth and sockets placed at the cardinal extrem- 
ities. Brachial valve with a broad cardinal plate or area extend- 
ing for the entire length of the hinge ; at its center is a callosity 
or cardinal process, which is supported by a median septum. 
Loop like that of Magas. 
Type, Rhynchorina spathulata, Wahlenberg (sp.). 
Distribution. Cretaceous. 
Kraussina, Davidson. 1859. 
Synonym ; Araussia, Davidson, 1852. 
Shells biconvex, plicate, subcircular or oval; hinge-line straight; 
foramen large, deltidial plates incomplete. Interior of the bra- 
chial valve with cardinal process and median septum. Brachi- 
146 
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