The first seven pairs of ribs have both tubercle and head. The first is nearly as long as the second, and is very broad at the proximal end. In the seventh pair the head is double, one facet of the rib articulating with the facet on the posterior margin of the centrum of the sixth thoracic vertebra and the other with the short transverse process on the side of the centrum of the seventh thoracic vertebra. The eighth and ninth pairs of ribs articulate only with the transverse processes of the eighth and ninth thoracic vertebræ, respectively. The ninth pair of ribs, as already stated, is nearly or quite as long as the eighth, from which it seems probable that a tenth short pair was present originally. There is, however, no trace of a facet for the articulation of such a rib on the end of the transverse process of what appears to be the first lumbar vertebra. The only difference between the ribs of _M. europæus_ and those of _M. bidens_ appears to be that the first pair is much longer proportionately in the former species. STERNUM. The sternum presents no differences of importance from that of _M. bidens_ figured by Grieg,[24] except that the fourth and fifth segments are anchylosed together, both laterally and transversely, and that the two sides are symmetrical. (Pl. 13, fig. 2.) PECTORAL LIMB. The scapula of _M. europæus_ presents an entirely different appearance from that of _M. bidens_ as figured in Van Beneden and Gervais’ Osteography (plate 22). In _europæus_ the scapula is very high anteriorly, the anterior border is convex forward and the anterior crest convex backward, bounding an elongated elliptical area. The posterior margin is straight. The acromion is short, with convex margins at the base, beyond which it narrows suddenly and terminates in a straight, cylindrical process, which is strongly inclined upward. The coracoid is as long as the acromion, nearly straight and horizontal, but expanded at the end. (Pl. 13, figs. 3, 4.) The phalangeal formula of the Atlantic City specimen of _M. europæus_ and those of three Norwegian specimens of _M. bidens_ are as follows (the metacarpals being included): _Phalangeal formula of M. europæus and bidens._ I. II. III. IV. V. _M. europæus_, Atlantic City: Left 2 6 6 3+ 3+ Right 2 7 6 4(+1?) 4 _M. bidens_: Landenæs 1 6(5) 5 4 3 Fæø 1 6 5 4 3 Udsire 1 6 6 5 4