1870. | LANKESTER—NEWER TERTIARIES OF SUFFOLK. 507 
agrees best with that, as well as the solid termination of the rostrum. 
But it is perhaps a legitimate question as to whether the forms of 
Choneziphius represented by Cuvier’s first specimen, by his second, 
by the cast sent by Prof. Van Beneden to Paris of a third, by the 
small cast in the British Museum, and finally by this new Suffolk 
specimen are not all varieties of age and sex of one species. Hype- 
roodon is known to be exceedingly variable in the characters of the 
rostrum within the limits of the same species, and so perhaps were 
the fossil ziphioids. If this is not the case it is very strange that 
nearly every new specimen of a ziphioid rostrum which turns up 
baffles all attempts at finding its counterpart, and requires a new 
specific name. Choneziphius Packard: stands certainly at one 
end of the series, the other extreme being represented by the small 
east of Choneziphius in the British Museum. Woodcuts of Cuvier’s 
Ziphius planirostris (fig. 1) and of 7. Cuviert (fig. 2) are here given 
for the sake of comparison with the plate*. 
I would direct the attention of those who are interested in the 
study of fossil Cetacea, and who have seen the Monograph of Crag 
Cetacea lately issued by the Paleontographical Society, to a paper 
published by me in 1867 on the structure of the tooth of JMicro- 
pteron Sowerbiense, in which I described the nipple-shaped tooth of 
Z. Layardi and Berurdius Arnuxn, as well as that of the tooth 
specially treated of, and drew certain conclusions as to the character 
of recent and fossil ziphioid teeth, which are now set forth afresh, 
without reference to that paper, by Prof. Owen; so, too, the views 
which I first advocated in this Journal as to the Diestien character 
of the Crag Cetacea are adopted without acknowledgment of any 
kind, though widely differing from Professor Owen’s former views. 
It should be remarked that the numerous sections of rostra given 
in the recent Monograph are purely imaginary, and that the sepa- 
ration of the bones marked 14 and 15 therein is hypothetical. Whilst 
no generic divisions of Ziphius are recognized, the specific name 
applied some years since by Prof. Huxley to a Belemnoziphius, 
namely ‘‘ compressus,” is taken by Professor Owen without any ex- 
‘planation, and applied as his own to another species. As a reply 
to assertions on the last page of the Monograph, I am glad to be 
able to mention here that I have obtained a Cetacean tooth of the 
Zeuglodont type from Suffolk. I mentioned its occurrence in the 
‘ Geological Magazine’ (1868); it is probably one of the foliaceous 
molars of the Squalodon antverpiensis of Van Beneden and Gervais. 
LY. Tus TritopHopont Masropon or THE SUFFOLK BoNnzE-BED 
(Plate XXXIV. figs. 1-4). 
In the ‘ Geological Magazine’ for 1869, I briefly noticed the oc- 
currence of a trilophodont Mastodon in the Suffolk bone-bed, having 
observed an upper penultimate molar in the collection of Mr. Baker, 
of Woodbridge, which indicated such a form. This specimen is drawn 
* I have to thank the authorities of the Paleontographical Society for the 
loan of these figures.—E. R. L. 
20 2 
