12 THE VOYAGE OF H.M.3. CHALLENGER. 



partial ossification. A pair of foramina opened on the outer surface of the occipital bone 

 immediately behind the foramen magnum, and the canals continuous with them running 

 vertically upwards in the substance of the supra-occipital, opened again on the surface 

 below the occipital crest, the distance varying in different specimens ; the canals and 

 foramina probably transmitted veins, and may appropriately be named supra-occipital. 

 The basi-occipital was not perforated, and in the older skulls was marked by a transverse 

 ridge. A slight paroccipital process was present in the older males, but in the young male 

 and the females it was just visible. The mastoid was scarcely differentiated as a process. 



The lower jaw was much more massive in the males than females, due in part to the 

 magnitude of the canine teeth and the size of the areas of attachment of the muscles 

 of mastication. In none of the specimens had fusion at the symphysis taken place. The 

 lower border of the body of the bone was slightly everted and terminated abruptly 

 behind in one of the males, but not in the other or in the females. At the posterior 

 border of the ascending ramus a subcondyloid i^rocess projected backwards a little 

 below the neck of the bone. The condyle was transversely elongated, the coronoid 

 process was low, and the sigmoid notch was shallow. 



Spine.- — The description of the bones of the neck, trunk, and limbs has been based 

 upon the study of the skeleton of the well-grown male (e) from Betsy Cove, Kerguelen, 

 though the skeletons of the younger specimens have been also examined. In no specimen 

 were the plates ankylosed to the bodies, and the cartilaginous tips of the spinous, trans- 

 verse, and mam miliary processes were unossified. 



The vertebral formula was C 7, D 15, L 5, S 3, Cd 10 = 40. 



The cervical vertebrae, except the 7th, possessed a foramen at the root of the 

 transverse process ; in all except the axis this process was a massive bar of bone 

 projecting downwards and outwards, but not flattened into a plate except in the atlas. 

 Evidence of the presence of two tubercles at the end of this process was seen in all 

 except the axis and the 7th. The spinous process was feeble, except in the axis, where 

 it was massive. The articular processes were autero-posterior in direction, the anterior 

 pair looked upwards and inwards, the posterior pair downwards and outwards. The 

 bodies were elongated transversely. The atlas had plate-like transverse processes which 

 projected outwards and very slightly downwards ; the articular surfaces for the occipital 

 condyles were deeply concave, and separated from each other by a distinct interval ; the 

 lamina on each side was perforated by a foramen for the vertebral artery. The articular 

 surface for the odontoid was continuous with the posterior articular facets for the axis, 

 and they were covered by a common plate of cartilage. The axis had a well-marked 

 odontoid process and the bone showed the remains of the intervertebral disc between 

 this process and the body of the axis. A broad plate of cartilage covered the inferior 

 surface of the process, which was separated from the cartilage covering the anterior 

 articular surfaces by a narrow groove on each side. The surface of the odontoid for the 



