242 TEETIART VEETEBKATA OE THE FATtTM, 



next tooth {pm. 3) is separated by an interval of about 6 cm. : it is likewise two-rooted, 

 and is much larger than pm. 2 • it can be seen that the posterior border of the crown 

 had at least three 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 

 {pm. 4) is almost in contact with pm. 3, to which it is closely similar in form ; its 

 antero-posterior diameter is 6'2 cm. Immediately behind pm. 4 come three closely 

 crowded molars, which differ from the premolars 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'.') cm. ; 

 they are so closely crowded that the hinder border of the penultimate fits into a groove 

 on the front of the last. Beneath the molars the depth 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-Qarun age, and associated 

 with remains of Frozeuc/lodon, of a large nearly complete skull measuring 116 cm. 

 in length. This may belong to either Fraas's species Eocetus schweinfurthi or to the 

 present form ; but, judging only from a rough photograph by Mr. Beadnell of the 

 occipital surface of this skuli, it seems that the former alternative is the more likely, 

 since the breadth of the supraoccipital region appears to be greater than in Zeuglodon 

 proper. 



The following specimens are provisionally referred to this species : — 

 C. 10019. A number of posterior lumbar and anterior caudal vertebrae of large size. Of these, two 

 are from the lumbar region (see text-fig. 79) and are closely similar to those of Z. macro- 

 spondi/lus, figured by J. Miiller * on his pi. xv. The ends of the centrum are oval in 

 outline, and in each case the epiphysis has been lost. The ventral surface is convex from 

 side t» side, particularly near the posterior 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 

 upper surface is a ridge which gives them the appearance of consisting of outer and 

 inner elements, though in section this is found not to be the case. Above the base of 

 the transverse processes the side of the centrum is concave. The neural arch, which 

 occupies about half the total length of the centrum, is situated towards its anterior 

 end ; it is very low, and the floor of the neural canal is concave both from 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 neither the anterior nor the posterior zygapophyses are developed ; the posterior 

 part of the arch bears a low neural spine and is produced back in the middle line 

 inlo a blunt point overhanging the posterior opening of the neural canal. In another 

 specimen, apparently a little further back in the series, there is a deep notch for the 

 passage of a vessel on the anterior border of the transverse process. Further back 

 still in the caudal region this notch is converted into a foramen perforating the base of 

 the process. In the caudal region- the metapophyses become very large and massive 



* ' Ueber die fossilen Reste der Zeuglodonten von Nordamerica ' (Berlin, 1849). 



