REPOET ON THE CETACEA. 17 



Zealand specimen, the fangs being little curved, the caps are thus almost parallel to the 

 fangs, or only slightly inclined outwards from them, whereas in the Cape specimen the 

 caps are directed at right angles to the fangs, which, towards their tips, are so bent as 

 to be almost horizontal. The alveolar regions of the fangs present in both specimens 

 a similar series of ridges terminating in denticulations. Tlie tips of all the denticula- 

 tions are closed in the New Zealand specimen, and there is no trace of a pulp-cavitv, 

 notwithstanding that the animal may be assumed to be young and with its teeth yet 

 to grow, which it would do by a continuous addition from without by a periosteum 

 which acts the part of a persistent pulp. 



" The New Zealand teeth are much less curved than those from the Cape. If the den- 

 tinal caps are placed in apposition and parallel to one another, the younger New Zealand 

 teeth are seen to be nearly two and a half times as broad as the older teeth from the 

 Cape at the place of attachment of the caps of dentine. In each case the cap is placed 

 on the anterior corner of the somewhat square-ended tooth, hence a large portion lies 

 behind the cap in the New Zealand specimen, and but a small portion in the one from 

 the Cape. On the anterior margin of the New Zealand teeth are semilunar excava- 

 tions, cutting into their substance, and evidently caused by wear. The inner more 

 spongy substance of the tooth being exposed it has decayed somewhat, leaving a harder 

 external layer a little prominent. This decay is probably a iJost-mortem occurrence. In 

 the Cape specimen there is no trace of this wear, or a very slight depression may possibly 

 mark it. 



"The dentinal cap of the tooth in the New Zealand specimen is marked by grooves 

 passing in an inclined direction from apex to base. Similar grooves are to be seen in 

 the tooth of the young specimen of Mesoi^lodon hectori in the Wellington Museum, the 

 tooth being divided by them into three lobes, a central and two lateral, on the inner 

 fiice. The adult New Zealand specimen shows the same form in its dentinal caps, 

 the lobes being on the inner face, and a pair of teeth of the same species from the 

 Chatham Island, preserved in the Museum, show the same form also. In the teeth of 

 the young Mesoj^Iodon hectori, the pulp-cavity is still open as a slit-like cavity, showing 

 internally numerous fine ridges, which are apparently the commencement of the den- • 

 ticulations of the adult tooth." 



In the skull described by Dr von Haast, the length of the anterior edge of the 

 exposed part of the tooth was 874 inches, and the anterior edge was not worn away; 

 but both in it and the Chatham Island specimen, described by Dr Hector, a sufiicient 

 space existed between the upper ends of the pair of teeth to allow of the beak to 

 pass, when the animal opened its mouth. Dr von Haast states that the animal was 

 a full-grown male, and from the ossification of the epiphyses, he judges it to be of 

 mature age. 



The tooth of a ziphioid cetacean, from Little Bay, Sydney, figured by Dr Gray, 



(ZOOL. CHALL. EXP. PART IV. — 1880.) D 3 



