anything to do with the aquatic life is not so clear. It also characterises the Sirenia, more or less, and the Otters; but, on the other hand, the terrestrial Bears show the same structure as do also some Ungulates. It must be borne in mind, too, that the kidneys of foetal Man are lobulated.
The liver is a compact organ not showing such lobulation as is common, but not universal, among mammals.
The bones of Whales have a somewhat loose structure, and are much impregnated with oil. In many features the skeleton of Whales is highly distinctive of the order.
Fig. 183.—Skeleton of Porpoise (Phocoena communis), acr, Acromion process of scapula; cerv, united cervical vertebrae; chev, chevron bones; cor, coracoid process; hu, humerus; hy, hyoid; jug, jugal; lumb.trans, lumbar transverse processes; max, maxilla; nas, nasal; orb, orbit; par, parietal; pelv, vestige of pelvis; per.ot, periotic; pr.max, premaxilla; rad, radius; rb1, first rib; rb12, twelfth rib; sc, scapula; s.occ, supra-occipital; st, sternum; uln, ulna; zyg, prezygapophysis. (From Parker and Haswell's Zoology.)
The brain case is small proportionately and rounded. The "face" is therefore long, and in some cases, especially among the fossil forms of Platanistidae, the rostrum is extraordinarily elongated. The asymmetry of the Whale's skull is one of its most remarkable features; this, however, is entirely limited to the Toothed Whales, and among them is more pronounced in some forms than in others. Thus the Platanistidae and many Ziphioids are not nearly so asymmetrical as the Dol-
