294 



DELPniNID.E. 



these all arise, I believe, from difference of age. One is perfectly 

 adult ; the suture between the frontal and occipital bones is entirely- 

 obliterated ; the upper ends of the maxiUaries are anchylosed to the 

 frontal ; the teeth, though pointed at the tips, have a polished sur- 

 face, and many of them are worn at the sides by the mutual action 

 upon each other of the upper and lower series. In the other skull 

 the ossification of the sutures is less advanced ; the teeth show no 

 signs of wear, and have a uniform slightly rufous or granulated sur- 

 face. This skull differs from the other, as will be more particularly 

 shown by the measurements, in having the facial portion and all the 

 ridges and outgrowths of the cranium for the attachment of muscles 

 much less developed in proportion to the size of the cerebral cavity. 

 In all essential specific characters they agree. Unless otherwise 

 expressed, the description and comparisons which follow refer to the 

 adult skull. 



" The principal dimensions of the two skulls in the Royal College 

 of Surgeons are as foUows : — 



Length from tip of beak to condyles 



Internal length of brain-cavity 



Length of beak (from a line drawn between tlie maxillary "I 



notches, to the tip) J 



Length from tip of beak to anterior margin of superior nares. 

 Length of palate (from tip of beak to posterior margin in \ 



middle line) J 



Length from tip of beak to hinder edge of posterior tooth ... 



Height of skiill at vertex 



Greatest breadth (at zygomatic processes of squamosals) 



Breadtli of brain-case in parietal region 



Breadth at supraorbital ridge 



Breadth of the base of the beak, inside maxillary notch 



Breadth of tlie middle of the beak 



Breadtli of the two premaxillai'ies, with their intervening | 



space at tlie middle of the beak J 



Width of condyles 



Foramen magnum, height 



Foramen magnum, width 



Lower jaw, entire length of each ramus 



Lower jaw, from tip to the posterior edge of last tooth 



Length of symphysis 



Height of ramus, at coronoid process 



Width, posteriorly, between outside of articular surfaces . . . 



" The teeth are nearly circular in section, stout, conical, pointed, 

 incurved, and very slightly recurved. The crowns of the largest 

 measure 1'2 inch in length, and 0-65 inch in diameter at the base. 

 With the exception of the two anterior and the posterior, they are 

 of very nearly cqiTal size throughout. Their number is the same in 

 both skulls, viz. eight on each side above, and ten below ; but though 

 the whole number is the same, I suspect that it is not exactly the 

 corresponding teeth which are in place in both specimens, at all 



