228 
TERTIAEY VEllTEBRATA OF THE FAYCM. 
is strongly developed on the inner side of the cutting-talon, which is slightly notched in 
the middle. The talon of m, 1 is composed of an outer cusp, a very small posterior and 
a rather larger inner tubercle belonging to the cingulum, the three surrounding a 
shallow depression. The dimensions (in centimetres) of the teeth are: — 
Length. Width. 
W. 1-9 1 
m. 2 1-8 -9 
m. 1 1'3 -6 
M. 8873. Plaster cast of the above specimen. 
Made in the British ^^aseulH. 
M. 8437 a. Portion of right ramus of mandible with greatly worn and broken cheek-teeth. 
M. 8437b. Portion of right ramus of mandible with pm. 2 and 3 complete, the other cheek-teeth 
broken and worn. Figured on PL XIX. fig. 4. 
M. 8436. 
Posterior portion of right ramus of mandible with m. 2 and m. 3. 
Figured on PI 
XIX. 
Text-fi". 73. 
Portion of right ramus of mandible of Apterodon macrognathus : A, from above; B, from outer side. 
pm. 4, fourth premolar; m. 1-3, the molars. | nat. size. 
The following specimens are referred provisionally to this species : — 
M. 8439. Nearly complete axis vertebra. In this vertebra the centrum is very much depres.scd ; 
anteriorly its ventral surface is concave from side to side, but posteriorly there is a median 
keel terminating behind in a hypapophysis. The odontoid is much flattened dorso- 
ventrally ; its ventral surface for the atlas is limited ])osteriorly by a sharp ridge. 
The lateral surfaces are about as deej) as wide, their ventral borders la-ing j)roduced 
downwards considerably below the ventral surface of the n'st of the centrum. The 
backwairdly directed transverse processes are largo and long, extending considerablv 
behind the posterior end of the centrum ; the vertebrarterial canal is small. The neural 
canal is both wide and high. The neural spine is a very high hatehet-shaped plate 
projecting considerably backwards behind the rest of the verb'bra ; its postero-ventral 
border is much thickened. The posterior zygapophy.ses are massive projections, their 
