Benham. — On the Lesser Sperm Whale. 163 



Chevron Bones. 



The Bibs. — Of the thirteen ribs four are connected to the 

 sternum by sternal ribs. The first vertebral rib, as in other 

 cases, is much stouter and shorter than the following. It is 

 broad, compressed antero-posteriorly and expanded distally. 

 It has a distinctly marked "angle" near the proximal 

 extremity, below which it curves suddenly downwards and 

 inwards to meet its sternal rib. The proximal extremity 

 bears distinct capitulum and tuberculum, as Von Haast 

 noted, and herein our New Zealand specimens appear to 

 differ from Wall's specimen ; while in Physeter, which is its 

 nearest ally, Flower states that these are not separate and 

 distinct. 



The two articular facets are nearly of equal size, though 

 the capitulum is slightly the smaller. They are separated by 

 a small "neck" measuring 14mm. in length. This capitu- 

 lum articulates with a conspicuous facet at the side of the 

 hinder end of the cervical mass— i.e., of the 7th cervical 

 vertebra. The tuberculum, of course, articulates with the 

 transverse process of the first thoracic. 



The 2nd rib is much longer, but less stout ; it is flattened 

 and broad, however, like the first. 



The capitulum and tuberculum are separated by a distance 

 of 20 mm., the former being rather the larger facet of the two. 

 The angle is well marked, but less acute than in the first rib, 

 and the curvature is more gradual. 



In this and the following four ribs the capitulum articu- 

 lates with the posterior end of the preceding vertebra only, 

 and not with its own vertebra. 



The 3rd to 6th ribs are practically similar, but the cur- 

 vature is different, for in the first place the angle is less 



