the former is alone concerned with the glenoid cavity. It must therefore, one would suppose, correspond to the "coracoid" of the Monotremata, while the upper piece of bone is the epicoracoid process of that mammal. The Mammalia, therefore, higher as well as lower, differ from the reptiles in that the coracoid is formed of two bones, the exceptions being, among some other extinct forms, certain of the Anomodontia, a group which it will be recollected is the nearest of all reptiles to the mammals.
Fig. 30.—Distal extremity of the humerus to show Epicondylar Foramina. A, In Hatteria; B, in a Lizard (Lacerta ocellata); C, in the Domestic Cat; D, in Man. c.e, External condyle; c.i, internal condyle. In A the two foramina are developed (at i, the entepicondylar; at ii, the ectepicondylar). The only canal (†) present in the Lizard (B) is on the external ulnar side, in the cartilaginous distal extremity. In Man (D) an entepicondylar process (pr) is sometimes developed and continued as a fibrous band. (From Wiedersheim's Anatomy of Man.)
The Fore-limb.—The humerus is of varying length among mammals. A feature which it sometimes shares with the humerus of lower forms is the presence of an entepicondylar foramen, a defect of ossification situated above the inner condyle of that bone which transmits a nerve. The same foramen and an additional ectepicondylar foramen are found in the ancient reptilian type Hatteria (Sphenodon); it occurs also in the Anomodont reptiles. It is as a rule only the lower forms among mammals which show this foramen; thus it is present in the Mole and absent in the
