vertex

The vertex is orange-coloured, with a black line in the middle.

Its shape varies from triangular to orbicular, the mouth of the animal forming the vertex of the triangle.

In D. Aloeus and its affinities, they are arranged in a triangle, whose vertex is towards the head.

Those parts which lie on the outside of the posterior half of the eyes, between which the Frons and Vertex intervene.

The point midway between the vertex V and center of curvature C is called the principal focus, F.