392 ART. 2. — II. .^rxVr.suMOTo : 



Abbreviations used in the Explanation of Plates. 



A . . . . Adorai shield. 



Ai» . . Articular peg. 



AS . . .Articular shoulder. 



C . . . . Articular condyle of geuital plate or radial sliield. 



D . . . . Dental plate. 



F . . . . Oral frame. 



Or .... Genital plate. 



K . . . . Articular knob. 



i> . . . .Lateral arm plate. 



liF . . Lower muscular fossa. 



M. . . . Madreporic oral shield. 



o . , . . Oral plate. 



OS . . . Oral shield. 



p . . , . Peristomial plate. 



li . . Radial shield. 



s . . . , Genital scale. 



u . . . . Articular umbo. 



UF . . Upper muscular fossa. 



Y . . , . Ventral arm plate. 



