180 PKOFESSOR STRUTHERS. 



cuius. In Megaptera the outer surface is directed a little 

 upwards, and is gently and nearly uniformly convex. In B. 

 musculus the upper part of the neck is inclined inwards, the 

 lower part outwards. The whole outer surface of the neck is 

 thus more directed upwards than' in Megaptera. Also, in B. 

 musculus the upper half of the posterior third of the neck is 

 concave, and the lower third of the anterior half is flat. This 

 torsion of the neck in B. musculus, mainly from the inward in- 

 clination of its upper part and of the base of the coronoid process, 

 is a marked distinctive character. In Megaptera the outer 

 surface of the neck, vertically, remains little different from that 

 of the body till close to the condyle. 



Viewed on the inner side, the same difference in the vertical 

 direction is seen, and the axes of the body and neck are seen to 

 meet abruptly at the anterior edge of the dental foramen in B. mus- 

 culus, while in Megaptera the change is gradual and not great. 

 Differences at the Dental Foramen. — (1) It is much nearer 

 the condyle in Megaptera; from the back of the condyle, llf 

 inches in Megaptera, in B. musculus 16. (2) As seen from 

 behind, it is on a plane more internal in its relation to the 

 coronoid process in Megaptera. A vertical straightforward 

 plane passing through the outer side of the foramen, in Megap- 

 tera passes to the inner side of the coronoid process, in B. 

 musculus intersects the process. (3) The spine, prolonged 

 back from the inner edge of the foramen, is short (f inch in 

 length) in Megaptera, in B. musculus long (2f inch) and 

 pointed. (4) The notch below the spine goes forward beyond 

 the upper notch, in Megaptera I to h inch, in B. musculus 2 

 inches. (5) The groove (about 4 inches long) which ends in 

 the foramen has in Megaptera a broad concave floor, 2 inches 

 broad at the middle, the inner edge raised ; in B. musculus it 

 is only 1 inch broad at the middle, and slopes downwards. 

 The wall above the groove in Megaptera slopes upwards and 

 outwards ; in B. musculus it is vertical or overhanging. The 

 result is that the groove appears to the eye as if dug out from 

 above in Megaptera and as if dug out from the inside in B. 

 musculus. (6) The foramen is larger in Megaptera, vertically 

 3 inches, transversely 2h ; in B. musculus it is | inch less in 

 both directions. (7) What appears to be the mylo-hyoid groove 



