The brachia rise from a corresponding number of thecal plates, "radials (RR)."
These constituted the arms (brachia), and five definite radial plates of the theca were specialized for their support.
In this development of brachial extensions of the theca the genital organs were involved, and their ripe products formed at the ends of the brachia or in the branches therefrom.
Pelmatozoa in which epithecal extensions of the food-grooves, ambulacrals, superficial oral nervous system, blood-vascular and water-vascular systems, coelom and genital system are continued exothecally upon jointed outgrowths of the abactinal thecal plates (brachia), carrying with them extensions of the abactinal nerve-system.
7 The " power of the signs " was similarly distributed among the parts of the human body: Et quanquam communis eat tutela per omne Corpus, et in proprium divisis artubus exit: Namque aries capiti, taurus cervicibus haeret; Brachia sub geminis censentur, pectora cancro.8 Warnings were uttered against surgical treatment of a member through whose sign the moon happened to be passing; 9 and zodiacal anatomy was an indispensable branch of the healing art in the Middle Ages.