PEOFESSOE FLO WEE ON THE EECENT ZIPHlOID WHALES. 231 



protuberance, representing the deltoid ridge, with a shallow groove below it. Bather 

 higher than this, just below the commencement of the expansion for the head, on the 

 outer surface of the bone, is a roughened shallow depression. The articular surface 

 for the ulna encroaches for a space of 1J inch on the corresponding margin of the 

 humerus. 



The radius is a simple narrow flattened bone of almost equal breadth throughout. 



The ulna has more pronounced characters, having a very well-developed, broad, and 

 flattened olecranon, with a strongly marked groove in the middle of the outer side of 

 its upper border, apparently for the passage of a tendon, and which I have not observed 

 in any other Cetacean. The bone is considerably contracted in its upper third, and 

 expands moderately towards its lower extremity. 



Both radius and ulna have well-marked epiphyses at either extremity, including the 

 whole of the articular surfaces: that of the upper end of the ulna is united to the 

 shaft ; but the other three are still separate. 



The carpus (PL XXVIII. fig. 10) presents some unusual features in the mode of union 

 of its several elements with each other. All the bones which are met with in Hyperoodon 

 and the other Ziphioids appear to be present and well ossified. There is thus one bone 

 more (viz. the magnum) than in the ordinary Dolphins and in the Sperm- Whale. 



The scaphoid (s) and the lunar (I) have almost completely united, though a groove 

 shows their original limits. The cuneiform (<?), which is the largest bone of the carpus, 

 is united at its outer edge with the unciform (u) ; and a long bone to the distal side of 

 which the second and third metacarpals are articulated, represents the magnum (m) and 

 the trapezoid (td) coalesced as in the skeleton of Mesoplodon soweriyi at Brussels. 

 The bone, of the distal row, most to the radial side might well be considered the 

 trapezium ; but it represents the bone which, in other Cetacea, has been considered, 

 with good grounds, to be the first metacarpal. Excluding this, the number of carpal 

 bones are reduced by ankylosis to four. The arrangement on the two sides is precisely 

 similar. 



The second and third digits are of nearly equal length, the fourth (IV) not much 

 shorter ; the fifth ( V) is well developed and stands considerably apart from the others ; 

 the first (/) is very small and adpressed. The phalanges were artificially articulated 

 before they came under my observation; and some of the smaller terminal ones are 

 probably missing ; but the numbers present are, including the metacarpals, in the first 

 digit 2, in the second 5, in the third 4, in the fourth 4, in the fifth 3. 



Dirnensiom of the Bones of the Right Pectoral Limb. 



inches. 

 Scapula. — Height from middle of superior border to middle of external 



margin of glenoid fossa 14 



Length of anterior border, from anterior superior angle to 

 anterior margin of glenoid fossa 15 



