| The triangular habit suggested trigonal symmetry and a possible identification as hilairite or a contact-twinned form of gaidonnayite. |
| However, Rayor suspects that for webs with radial symmetry, the answer is a matter of biodynamics. |
| With neat transatlantic symmetry, it is known as the Press Association, PA for short. |
| These are, in order of decreasing symmetry, the cubic, hexagonal, tetragonal, trigonal, orthorhombic, monoclinic, and triclinic systems. |
| From the want of symmetry in the base of the specimen, I suppose it to have been the pectoral spine of some huge siluroid fish. |
| In this case, the c-axis, or axis of trigonal symmetry, is vertical with respect to the organic substrate and hence to the wall itself. |
