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.
Small persistent, 5-dentate calyx, 5 petals, 1 0 stamens, a sessile 3 to 5-chambered ovary, a long style, and a 3-lobed stigma; fruit trigonal or pentagonal; and seed compressed.
A four-chambered heart, with a complete double circulation, and warm blood (less markedly so in the lowest group than in the rest of the class), distinguish mammals from existing reptiles, although not from birds.
Carpenter's proof of the nervous nature of the chambered organ and axial cords of crinoids (Proc. Roy.
These last structures formed a nervous sheath around the axial sinus with its bloodvessels, and became divided into five lobes correlated with the five basals (the "chambered organ") and forming the aboral nerve-centre.