The rhomboidal peninsula of the Crimea, connected by only a narrow isthmus with the continent, is occupied by an arid plateau sloping gently N.
In Rhamphorhynchus there is also a rhomboidal expansion of membrane at the end of the tail.
5); the segments, which are broadly ovate or rhomboidal, have several forked spreading veins, and resemble the large pinnules of some species of Adiantum.
Fertilis, from the Pottsville beds (Millstone Grit) of West Virginia, the rhomboidal seeds, flattened and winged like those of Cordaiteae, are borne terminally on the lateral pinnae of a frond, which elsewhere bears the characteristic cuneiform leaflets.
The extinct Stegocephalia, on the other hand, were mostly protected, on the ventral surface at least, by an armour of overlapping round, oval, or rhomboidal scales, often very similar to those of Crossopterygian or ganoid fishes, and likewise disposed in transverse oblique lines converging forwards on the middle line of the belly.