564 DR. S, F. UARMEK OX 



and flat proximallj (pp. 35, 36), and the prenarial basin is un- 

 developed. It appears to me that these conclusions ai'e well 

 founded ; and applying them to the Unionhall specimen, there 

 seems eveiy reason to believe that it was a female. This con- 

 clusion is strengthened by the fact that the teeth of the apex of 

 the lower jaw do not cut the gam, although the dissection made 

 by Mr. Pycraft proved that they are present and of cousidei'able 

 size, projecting for about 25 mm. beyond the bone of the jaw 

 and nearly reaching the surface of the gum, and having a Ijasal 

 diameter of about 13"5 mm. It should be added, however, tliat 

 the Unionhall specimen was not fully adult, since the sutiares of 

 the skull are still extremely distinct, while the epiphyses of the 

 vertebrae are not yet ankylosed to the centra. 



It would be extremely desirable to be able to state characters 

 by which a Zlphius in the flesh can be distinguished certainly 

 from the other Ziphioid Whales ; but I am not prepared to do 

 this without further study of the subject. In the case of the 

 males, in their adult condition and probably at earlier stages of 

 their life, the occurrence of a pair of large teeth at the exti'eme 

 front end of the lower jaw and cutting the gum is probably 

 amply sufficient for recognition, particularly when taken in con- 

 junction with the absence of the enormously swollen forehead 

 so characteristic of the adult male Ilyperooclon. But a young 

 Ziphioid Whale of either sex, or an adult female which has no 

 teeth visible during life, is less easily referred to its proper 

 genus. 



It has already been pointed out that the Wexford specimen of 

 Z. cavirostris and von Haast's New Zealand specimen (1880, 

 pi. xxiii.) were white above and dark below — a type of coloration 

 which is by no means common in Cetacea. Other specimens 

 which have been referred to this species were, however, dark 

 above, even on the head, and light below. Making full allowance 

 for the uncertainty which so often prevails with regard to the 

 real colour of Whales, owing to post mortem changes and to the 

 fact that the examination frequently has to be made some time 

 after death and under unfavourable conditions, it must be con- 

 cluded, in the present state of the evidence, that Z. cavirostris is 

 a species of very vaiiable coloration {cf. True, 1910, p. 35). It 

 may further be noted that according to Van Beneden (1888, 

 p. 60) the rostrum and forehead of Hyperoodon become white in 

 polour with age. The projection of the lower jaw beyond the tip 

 of the snout is appai-ently a positive character of Ziphius ; 

 and the snout is probably less distinctly marked than in either 

 Mesoplodon or Hyperoodon, 



A further difficulty in defining the external characters of 

 Z. cavirostris arises from the uncertainty which prevails with 

 regard to the two mandibular teeth in the female. In some of 

 the published accounts of this sex, these teeth are descr-ibed as 

 visible during life ; while in the Unionhall specimen (probably a 

 ifemale) they were completely concealed beneath the gum. 



