When, as in the application to rectangular or circular apertures, the form is symmetrical with respect to the axes both of x and y, S = o, and C reduces to C = ff cos px cos gy dx dy,.
Such determinants are called symmetrical.
Few children have perfectly symmetrical teeth and a perfect bite.
In association with this movement in a definite direction the body has become vermiform and bilaterally symmetrical.
The spines are variously coloured, white and yellow tints predominating, and from the symmetrical arrangement of the areolae or tufts of spines they are very pretty objects, and are hence frequently kept in drawing-room plant cases.
