PALiEOMASTODON PAPVUS. 
1G5 
seen that tlic deltoid ridge (d.) formed a prominent oblique crest continued up to the 
greater tuberosity. The coronoid fossa (c.f.) is wide and moderately deeply concaves; 
the olecranon fossa is large and deep, particular!)’ on the outer side. The outer and 
inner (i.e, and o.c.) condyles are both fairly prominent, the latter projecting considerably 
backwards. The supinator ridge (s.r.) is short, much shorter relatively than in the 
humerus of I\ headnelli described above. The articular surface is divided by a broad 
groove into an inner larger (tr.id) and an outer smaller portion (tr.o,). The former 
bears a slight ridge which marks the separation of the surface for the radius from 
that for the inner portion of the ulna. The bone, as a whole, is very thin-walled and 
lightly built — a circumstance that may account for the extreme rarity of bones of 
Palceomastodon. The chief points by which this humerus differs from that of Elephas 
are : (1) the greater tuberosity is larger and rises more above the head ; (2) the 
supinator ridge is very much smaller, so that the distal portion of the bone is less 
expanded. 
M. 8889. Plaster cast of the above specimen. Made in the British Mnseurn. 
C. 8063. A similar right humerus wanting the proximal end. 
M. 8890. Plaster cast of the above specimen. Made in the British Buseujn. 
The dimensions (in centimetres) of the above humeri are: — 
0 . 8881 . 
Length 45’2 
Width of bead 9 
,, of shaft at narrowest 5'7 
,, lower end at widest 13‘8 
„ distal articulation 9'8 
0 . 8063 . 
43-3 + 
5‘4 
13 + 
10 
C. 8028. Nearly complete right ulna (text-fig. 57). The olecranon (o/. ) is large, greatly expanded 
at the end, and projecting strongly towards the inner side ; it does not rise above the 
upper angle of the articulation. This latter is triradiate in form ; the upper lobe 
projects strongly forwards, while of the lower two, the outer has a straight anterior 
border, beneath which is the elongated facet (r.s.) for the upper end of the radius; 
the inner is oval in outline and seems to have little or no contact with the radius. 
The whole shaft of the bone is curved backwards ; it is triangular in section, the anterior 
face being deeply concave from side to side near its upper end (r.g.) Distally it 
widens out somewhat, but the epiphysis having been lost, the distal articulation cannot 
be described. The whole ulna is practically that of a miniature elephant. The 
dimensions (in centimetres) of the specimen are : — 
Length (without epiphysis) 38 
Width of articulation for humerus 9 3 
„ middle of shaft 4-8 
M. 8891. Plaster cast of the above specimen. Made in the British Mnseiirn. 
M. 8858. Upper end of left ulna. Presented by the Egyptian Government , 1904. 
C. 8883. Right tibia (text-fig. 58). In form this bone is almost exactly similar to the tibia of 
P. headnelli figured on PI. XVI. fig. 4. In the proximal articulation the inner facet (i.) 
