Thus, while the long barrow is characteristic of the Stone Age, it is impossible to tell without direct examination whether it may be chambered or unchambered, or whether the burials within it may be those of burnt or of unburnt bodies.
Meath, there is a group of about thirty stone barrows or cairns, mostly chambered, their bases measuring from 5 or 6 to 60 yds.
In Ireland, where the long barrow form is all but unknown, the round barrow or chambered cairn prevailed from the earliest Pagan period till the introduction of Christianity.
The pyramids of Egypt, the mausolea of the Lydian kings, the circular, chambered sepulchres of Mycenae, and the Etruscan tombs at Caere and Vold, are lineally descended from the chambered barrows of prehistoric times, modified in construction according to the advancement of architectural art at the period of their erection.
It is characterized by the presence of a special development of the lophioderm or median fin-system, namely, the ventral fin, which is composed of two portions, a lower keel-like portion, which underlies an upper chambered portion, each chamber containing typically a pair of gelatinous fin rays.