Red blood corpuscles

(Physiol.)

in man, yellowish, biconcave, circular discs varying from 1/3500 to 1/3200 of an inch in diameter and about 1/12400 of an inch thick. They are composed of a colorless stroma filled in with semifluid hæmoglobin and other matters. In most mammals the red corpuscles are circular, but in the camels, birds, reptiles, and the lower vertebrates generally, they are oval, and sometimes more or less spherical in form. In Amphioxus, and most invertebrates, the blood corpuscles are all white or colorless.