Surface armed with very numerous (sixty to eighty) strong conical spines, about as long as the minor axis of the shell.
We must now get the diameter of the minor axis, along the line B.
The arches which stood at the extremities of the minor axis were the approaches to the imperial pavilions.
Polar spines sharp edged, more or less curved, the shorter equal to the minor axis, the longer twice as long.
minor axis three times as large as that of the inner spherical shell; pores of the latter, small, circular.
minor axis twice as long as the diameter of the inner spherical shell, which has regular, simple, circular pores of half the size.
The minor axis or greatest breadth is about one-half the major axis or length.
Polar spines three-sided pyramidal, about as long as the minor axis, as broad at the base as one hexagonal frame.
The marks D D, therefore, indicate the distance across the minor axis in Fig. 113.
Draw the line a b, the major axis, and at a right angle to it the line c d, the minor axis of the figure.