230 PROFESSOR FLOWER OX THE RECENT ZIPHIOID WHALES. 



resembles generally the form of the same part in Ziphius and Mesoplodon, but is pro- 

 portionally longer than in Hyperoodon, and still more than in Physeter. The inferior 

 surface is slightly convex from before backwards, and also from side to side. 



It consists of five distinct segments, not connected together by bone. The anterior 

 segment is the largest, and has a shallow fossa in the middle line in front ; the posterior 

 segment ends in a pah of narrow xiphoid processes, of which the right is slightly larger 

 than the left. 



As in the other Ziphioid Cetaceans, development is less complete along the middle 

 line of the sternum than at the sides; not only are there median notches at each 

 extremity, but there are three large median fenestra, one between the first and second 

 segments, one between the second and third, and one between the third and fourth seg- 

 ments. The edges of these fenestra are bevelled and smooth ; so that it does not appear 

 that ossification would have advanced further in this direction if the animal had lived 

 to be older. 



Each side of the sternum shows six rough articular facets for sternal ribs : — the first 

 near the anterior end of the first segment, at its broadest part; the second at the 

 junction of the first and second segments; the third at the junction of the second and 

 third segments ; the fourth at the junction of the third and fourth segments ; the fifth 

 near the hinder end of the fourth segment ; the sixth on the side of the fifth segment, 

 near its anterior end. 



The entire length of the sternum in a straight line is 45 inches. The greatest breadth 

 of the first segment is 12-8 inches, of the second segment 10-9 inches, of the third 

 10 inches, of the fourth 9 inches, of the fifth 8*8 inches. 



Pectoral Limb. — The pectoral limb, as in all other members of the group to which 

 Berardms belongs, is small in proportion to the size of the animal. 



The scapula bears a considerable resemblance to that of Hyperoodon ; it is less narrow 

 and elongated than in Physeter, and more regularly triangular, and less fan-shaped 

 than in the ordinary Dolphins. The external surface is smooth and slightly concave, 

 with one vertical ridge near the hinder border. The acromion is large and flat, curving 

 regularly inwards, and somewhat upwards towards the extremity. The coracoid is 

 rather longer, and more slender and rounded than the acromion. The glenoid fossa is 

 irregularly oval, the outer edge more convex than the inner, and the anterior extremity 

 more pointed than the posterior. 



The humerus and bones of the forearm are elongated, slender, and simple in 

 character; the latter more resemble the corresponding bones of a Balcenoptera than 

 of one of the Delphinidse. 



The humerus has a rounded head and single tuberosity, formed by a large and still 

 free epiphysis. The lower epiphysis includes little more than the articular surface, 

 and is united to the shaft, though the line of separation is distinct in many points. 

 The radial border of the bone presents, near the middle of its length, a low rounded 



