SCHULTE, SEI WHALE. 489 



sufficient number of observations, the constancy or preponderating frequency in that given 

 species of the structure in question. The doubt of the normality of the cervical rib in B. borealis, 

 is only such as is incident to the necessarily limited number of individuals examined of an animal 

 so difficult to procure. 



The sternum. The sternum is lozenge-shaped with produced angles; the elongation of 

 the caudal one is much less than in Fischer's, 1 or even Flower's 2 illustration of the adult bone. 

 It measures 13.5 mm. in breadth by 11.5 mm. in length. Its caudal margin rests against the 

 ventral extremities of the rib of the first pair, and the short caudal process is inserted between 

 them. It is joined to the ribs by a firm connective tissue, without the presence of a joint cavity. 



THE PECTORAL LIMB. 



Scapula: The scapula is rather low, its length being nearly twice its breadth (40 mm., 

 22 mm.). The vertebral border presents three convexities separated by slight concavities. 

 The caudal border is concave near the neck, slightly convex at the distal limit of the teres origin, 

 and thence nearly straight to the caudal angle which is rounded. The cephalic border is slightly 

 convex as far ventrad as the acromion, and in this part of its course beveled and separated by 

 a low ridge from the dorsum. As this ridge defines the limit of the supraspinalis origin it is taken 

 to represent the spine of the scapula and the beveled margin corresponds to the supraspinous 

 fossa. The acromion is very long, its extremity lying vertically below the cephalic angle. Its 

 borders dorsal and ventral are parallel; its tip is blunt; only its base is ossified. The venter 

 of the scapula is very slightly concave at its junction with the neck, elsewhere flat. The cora- 

 coid is robust, tapering slightly to its summit. It is directed cephalad and to a less degree ventrad 

 and mesad. It is wholly cartilaginous. The glenoid fossa is deep with prominent thin margins. 

 Its shape is nearly triangular owing to the marked projection of its dorsal border in a rounded 

 angle. The articular surface is almost wholly formed by the scapula. To the base of the cora- 

 coid as it presents in the joint-cavity is attached a strengthening band of the capsule, visible 

 from within the joint and continuous with the fibrous bands of the flexor surface of the humerus - 

 a fact which fully justifies their interpretation as bicipital rudiments. The ossification includes 

 the greater portion of the blade, the cephalic and caudal borders and extends into the neck 

 and the base of the acromion, leaving the parts adjacent to the vertebral margin (suprascapula), 

 the glenoid region, and the whole coracoid still cartilaginous. The surface for muscular origin 

 is increased by two strong aponeuroses. One at the caudal margin stretches across the concavity 

 between the origin of the teres and the glenoid margin and serves as an intermuscular septum 

 between this muscle and the subscapularis. The other stretching between the dorsal margin 

 of the acromion and the ridge representative of the spine increases the surface of origin of the 

 supraspinatus and deltoid muscles. 



Humerus. The humerus is short and stout, its long axis oblique from the shoulder caudad, 

 ventrad and slightly laterad. The head which looks chiefly dorsad, to a less degree mesad and 

 cephalad, meets the shaft at an obtuse angle. The articular surface is globular except that it is 



1 Fischer, M. Ce'tace'es du sud-ouest de la France. Actes Soc. Linn. Bordeaux, 1881. Quoted in Beddard, F. E., A book of whales. 

 New York, 1900. PI. iii, fig. 10a. 



1 Flower, W. H. On a specimen of Rudolphi's rorqual taken recently on the Essex coast. P. Z. S., 1883, p. 513. 



