480 DR. J. V. HAAST ON MESOPLODON FLOWERI. [June 6, 



Measured on the drawing of that bone in the figure given by Prof. 

 Owen, the total length of the lower jaw of M. layardi, from the point 

 to the angle, is to the greatest depth as 84- to 1, whilst in the New- 

 Zealand specimen it is as 6^ to 1 . In 31. layardi the lower jaw is 

 much more slender, the upper and lower border being very slightly 

 inclined to one another, whereas in 31. flower i the two borders form a 

 much more open angle with one another, the upper border being very 

 convex near the coronoid process. If both skulls were available for 

 comparison side by side, I have no doubt that other differences would 

 be detected, especially by a comparative anatomist of more experience 

 than I possess. 



There is an important difference in amount of curvature of the 

 large tooth on each side of the lower jaw, which in the Cape speci- 

 men is so much arched that the apices of both teeth actually meet 

 above the rostrum, a peculiarity which the late Dr. Gray thought 

 could scarcely be a malformation. In the New- Zealand specimen 

 that curvature, although existing, is not so pronounced, the point of 

 the tooth standing in a vertical line above the centre of the root. 

 Its form and position agree entirely with those of the tooth of a lower 

 jaw brought from the Chatham Islands by Mr. H. Travers, and de- 

 scribed and figured by Dr. Hector as Dolichodon (Mesoplodon) 

 layardi in the fifth volume of the 'Transactions of the New-Zealand 

 Institute.' Behind this mandibular tooth there is no partial hollow 

 on the upper margin of the lower jaw, as if it were the cavity of an 

 old tooth that had fallen out, as is the case in the Cape specimen, 

 and which was first pointed out by Dr. Gray in his ' Catalogue of 

 Seals and Whales in the British Museum.' The New-Zealand spe- 

 cimen under review thus conforms also in this respect to the lower 

 jaw obtained in the Chatham Islands. 



The anterior edges of both teeth, however, are perfectly intact, and 

 not worn away like those in the Cape and Chatham Island specimens ; 

 a peculiarity which might be traced to individual habits, and is, I 

 suppose, not of any specific value. There is no doubt that the 

 New-Zealand*and Chatham-Island specimens couldopen their mouths, 

 as there is sufficient space for the rostrum to pass between the apices 

 of the teeth. However, there has evidently been some abrasion on 

 the inner side of both teeth near the crown, as they are here some- 

 what worn down and polished. The small enamelled portion rising 

 on the anterior edge of the apex is not quite so large as in the Cape 

 specimen. 



The lower jaw from the Chatham Islands is T75 inch shorter 

 than that of the specimen under review, in which latter the mandi- 

 bular tooth is also much longer, which may be regarded as an indi- 

 vidual difference only. 



The following Table of measurements will also supply further 

 material for comparison : — 



Dimensions of the skull. ft. in. 



Extreme length of cranium 3 5" 75 



Length of rostrum from the apex of the prse- 



