34 
NOMENCLATURE. 
MULTI VALVES. 
Basis. Base ; in Chiton and Lepas, that part of 
the shell which is affixed to extraneous 
bodies, either with or without a Peduncle ; 
in Pholas, as in Bivalves, the part of the 
margin opposite to the summit of the beaks. 
Ligamentum. Cartilage; the membrane 
which connects the valves. 
Limbus. Border; the marginal membrane of 
Chiton. 
Operculum. Operculum; in Lepas, the lid 
which closes the vertical aperture, consist- 
ing usually of four triangular valves. 
Pedunculus. Peduncle; the tubular support 
of certain Lepades. 
coriaceus. Coriaceous ; like leather. 
Valv^. Valves. 
do7'sales. Dorsal ; the solitary valves in the com- 
pressed quinquevalve species of Lepas. 
succenturiatcd. Accessory ; those smaller irregular 
valves which are annexed to the hinge of 
' the Pholades. 
