xxii 
EXPLANATION 07 TERMS. 
Confluent. Running into each other. 
Convolute. Rolling regularly over each other. 
Coriaceous. Of a tough leather-like substance. 
Crenate, Notched in a rather undulating manner. 
Crown. The top of the shell. 
Cylindrical. Elongated and rounded, and of equal diameter 
throughout. 
Decorticated. Worn down, as if by accident or design. 
Decussate. Furnished with fine lines both lengthways and 
across. 
Denticles. Small tooth-like protuberances. 
Denticulate. Furnished with denticles. 
Dorsal. Appertaining to the outer-surface, or back part of 
the shell. 
Duplicature. A fold tending backwards. 
Ears. Appendages on the sides of the hinge, as in most of 
the Scallops. 
Effuse. Having the aperture expending from one end of the 
shell to the other, and open at both extremities. 
Emargmate. Notched. 
Ferruginous. The color of rust or iron-mould. 
Flexuoxu. Running in a waved or indented manner. 
Fusiform. Shaped like a spindle; swollen in the middle, 
and tapering to each end. 
Gape. 'I he opening in some of the bivalve shells, when the 
valves are closed. 
Genus . A separate family, distinguished from all others by 
certain permanent marks, called generic characters, and to 
which all such belong as are furnished with these characters ; 
as the bivalves are known by the hinge and the teeth. 
, Glabrous. Quite smooth, and without wrinkles, lines or 
ridges. 
Granular y or Granulate. Covered with pimples or small 
wart-like protuberances. 
Gutter. The elongated projection beyond the mouth in 
some of the Murex tribe. 
Habitat. The natural local habitation of a shell, or the place 
where it is generally found. 
Hinge. The upper part of bivalve shells, where the teeth 
and connecting cartilage are placed. 
Hyaline. Transparent like glass or water. 
Inflected. Bending inwards. 
Imbricate. Lying over one another, like the tiles of a house. 
Involute. Turning or rolling inwards. 
Irregular. 
