242 
TERTIARY VERTEBRATA OF THE FATOm. 
next tootli (/n». ?>) is sepanitod by an interval of about (i cm. : it is likewise two-rooted, 
and is inucli larger than pm. 2 ; it can l)e seen that the posterior border of the crown 
had at least I hrec accessory denticles, of which the uppermost is the largest; the summit 
of the crown is broken away ; the antero-posterior width is 6'2 cm. The next tooth 
4) is almost in contact with pm. 3, to which it is closely similar in form ; its 
antc'ro-posterior diameter is G'2 cm. Immediately behind j/m. 4 come three closely 
crowded molars, which differ from the ]>remolars in having no accessory denticles 
on the anterior border and only one or two on the posterior. These teeth increase 
in size from before backwards, the last having an antero-posterior width of 4‘5cm.; 
they are so closely crowded that the hinder border of the })enultimate fits into a groove 
on the front of the last. Beneath the molars the de])th of the mandible increases very 
rapidly, so that they are arranged in a steeply sloping line. 
Mr. Beadnell records the discovery in beds of Birket-el-Qurun age, and associated 
with remains of Frozeuplodon, of a large nearly complete skull measuring IIG cm. 
in length. This may belong to either Fraas’s species Eocetits sclmehifurthi or to the 
present form ; but, judging only from a rough photograph by Mr. Beadnell of the 
occij)ital surface of this skull, it seems that tlie former alternative is the more likely, 
since the breadth of the supraoccipital region appears to be greater than in Zeuglodoii 
proper. 
The followdng specimens are provisionally referred to this sj)ecies : — 
C. 10019. A number of posterior lumbar and anterior caudal vertebra} of large size. Of tlicse, two 
are from the lumbar region (see text-tig. 79) and are closely similar to those of Z. niacro- 
.yxmdi/htSj figured l)y J. Muller * on his pi. xv. The ends of the centrum are oval in 
outline, and in each case the epiphysis has l)een lost. The ventral surface is convex from 
side to side, ])articulariy near the ])osterior end; in the middle is a depression into which 
a pair of vascular foramina open. The transverse processes are fairly large and project 
forwards and downwards; they are strongly flattened from above downwards; on their 
ujiper surface is a ridge which gives them the a])pearance of consisting ot outer and 
inner elements, though in secti(m this is found not to be the case. Al)ove ihc base of 
the transverse jirocesses the side of the centrum is concave. The neural arch, which 
occn])ies about half the total length of the centrum, is situated towards its anterior 
(‘ud ; it is very low, and the floor of the neural canal is concave both li-om side to side 
and from before backwards; at the bottom of the concavity there is a large vascular 
Foramen. Anteriorly the arch bears a pair of large quadrate metapophysial processes, 
but neitluM’ the anttudor nor tln^ posterior zygapophyses arc develoj)ed ; the posteiaor 
]iart of tlui arch beai’s a low muiral spine and is prodiuanl back in tlui middh^ line 
inlo a blunt jioint overbanging the jiosterior opening of the m-ural canal. In another 
specinum, apparentlv a litth; turther baede in th<! scudes, tlieia^ is a dee]) notcdi tor the 
passage of a vc'sscl (ui tho anterior border of the ti'ansvorse ])rocess. Further batdc 
still in the caudal region this nottdi is converted into a foramen jicrlorating the base of 
the ])roccss. In the caudal region the m(‘tai)oj)hyses become very large and nuussivi' 
* ‘ Ueber (lie fo.ssileii Reslu dcr Zeugloduuteii (on Mordiuucidca ' ( Ikudiu, 1819). 
