56 Ray Lankester, on the Tooth in Ziphius Soive'rbiensis. 
snout so as to prevent the opening of the mouth beyond a 
very limited extent, as in Ziphius ( Dolichodon ) Layardi , 
lately described by Dr. Gray, is certainly at present ob- 
scure ; still more .difficult is the explanation if, as it appears, 
the males only have these massive teeth. That these teeth, 
or rather one tooth of a certain Ziphioid, and probably also 
those of others, present marked differences in structural 
arrangement, distinguishing them from the teeth of other 
Cetacea, I hope to show in the following pages. 
As far as I have been able to ascertain from the writings 
of Yan Beneden, Gervais, Duvernoy, and others, no descrip- 
tion has yet been published of the dental tissues of any one 
of the Rhynchoceti, excepting a brief notice of the small 
pointed denticles in a species of Hyperoodon, given by Pro- 
fessor Owen* in his ‘ Odontography,’ from which it does not 
appear that there is any close analogy between Hyperoodon 
and Ziphius ( Micropteron ) in regard to the teeth ; and, in- 
deed, they have a very different position and time of appear- 
ance in the two forms. 
The synonymy of genera and species in the Rhynchoceti 
is likely to cause some confusion, and I shall therefore make 
use of the generic and specific terms approved by Professor 
Huxley in a very concise memoir on a fossil Ziphius, pub- 
lished in the e Quarterly J ournal of the Geological Society,’ 
1864, p. 395. 
The lower jaw and the larger part of the skull of the male 
specimen of the rare species Ziphius ( Micropteron ) Sower bi- 
ensis, which was thrown ashore in Elginshire in 1800, and 
was engraved in Sowerby’s ‘British Miscellany,’ 1806, p. 1, 
pi. i, is preserved in the Oxford University Museum, having 
been purchased by Dr. Buckland at the sale of Sowerby’s 
museum, and presented by him to the Anatomical Museum 
of Christchurch, whence it was transferred with the rest of 
the collection to the University building. 
I have been allowed to figure and describe the microscopic 
and other sections which have been made from the right lower- 
jaw tooth of this specimen, and Mr. Tuffen West has also had 
one of three sections entrusted to him for comparison with my 
drawings whilst engaged in the work of engraving them. 
A history of the Oxford specimen, as also a full biblio- 
graphy of the various memoirs which have appeared upon 
the anatomical and zoological relations of this animal, will he 
found in the ‘ British Museum Catalogue of Seals and 
Whales,’ 1866, p. 350. 
* See also Yrolik’s figures in his Memoir on Hyperoodon. Natural His- 
tory Society, Haarlem, 1848. 
