DESCEIPTION OF PLATES. 539 



in. Between extreme points of occipital condyles (external angles), 6'1 in. From 

 the basilar surface, between the occipital condyles to occipital crest, 7'5 in. Height 

 of occipital foramen, 1-9 in. Breadth of occipital foramen, 1'8 in. Greatest 

 breadth of upper surface of occipital condyle, 2" in. From occipital crest to 

 posterior border of posterior core, 1*2 in. Breadth of cranium beneath posterior 

 core (distance between outer margins of roots of posterior cores), 12-1 in. Extreme 

 distance between fractured extremities of posterior cores, 21-5 in. Transverse 

 diameter of posterior core before its expansion, 6'8 in. Transverse diameter of 

 root of posterior core, 8'4 in. Thickness of core before expansion, 3'1 in. Great 

 diameter (transverse) of posterior branch, 2'5 in. Thickness (vertical diameter) 

 of posterior branch, 1'6 in. Chord of arc between the origin of posterior branch 

 and occipital crest, 3'1 in. Thickness of stem (thickest part) of core, 3 '6 in. 

 Circumference of core before expanding, 16'8 in. Antero-posterior diameter of 

 broken end of anterior core, 4'1 in. Greatest transverse diameter of broken end 

 of anterior core, 3'2 in. Diameter of base of anterior core, 4'9 in. Breadth of 

 cranium beneath anterior cores (at foramen orbitale lacerum), 5'3 in. Between 

 inner margins of articular surfaces of occipital condyles superiorly, 1'7 in. Height 

 of fossa for insertion of ligam. nucliae, 3 '8 in. Base of fossa for insertion of ditto, 

 6'4 in. Groove between condyles, inferiorly, "45 in. Between outer margin of 

 condyles (inferiorly) immediately behind parieto-occipital crest, 2'7 in. From 

 grooves behind occipital condyles, inferiorly, to floor of fossa for ligam. nuchse, 

 3-7 in. 



This is the specimen referred to by Dr. Falconer at page 266, and 

 also figured in Plate XXI. fig. 2. 



Fig. 3. — Sivatherium giganteum. Fragment of cranium, showing 

 forehead, orbits, and cores of anterior horns. Tliis is the same specimen 

 as figured in Plate XCII. figs. 2 and 2 a.— B.M. 



Antero-posterior diameter of orbit, 4* in. Height of orbit, 2-7 in. Width of 

 malar bone, 2'7 in. Width between anterior angles of orbit, 11 -2 in. Width be- 

 tween outer margins of orbital cornua, 12- in. Long diameter of fractured end of 

 right horn, 5'18in. Short or transverse diameter of right horn, 3' 10 in. Probable 

 width between mastoid processes, 16- in. 



Fig. 4. — Sivatherium giganteum. Fragment from middle of posterior 

 horn. This specimen was in Sir Proby Cautley's collection, and was 

 found to correspond to the posterior horn-core in Col. Colvin's specimen. 

 It is also figured in Plate XXI. fig. 3, antea, p. 268.— B.M. No. 39,525. 



Length following curvature, 21" in. Circumference at lower attachment, 18- in. 

 Breadth at offset, 8'1 in. Length of offset at base, 5- in. Width of offset at base, 

 4'6 in. Breadth at fractured upper extremity, 6'8 in. Greatest thickness at upper 

 extremity, 2' 3 in. 



Fig. 5. — Sivatherium giganteum. Fragment from apex of posterior 

 flattened horn.— B.M. No. 39,524. 



Extreme length, 10-6 in. Breadth at base, 8'4 in. Thickness (extreme), 

 1-8 in. 



Plate B. 



Sivatherium giganteum. — Figs. 1, 1 a, and 1 b. — Fragment of atlas, 

 comprising lower arch. — B.M. No. 39,526. 



Extreme length of fragment, 8'3 in. Antero-posterior diameter of lower arch, 

 3-1 in. 



Fig. 2.— Atlas, very perfect.— B.M. No. 39,527. 

 Extreme breadth, 8'3 in. 



Figs. 3, 3 a, 3 h, and 3 c— Axis.— B.M. No. 39,528. 



Extreme length, including odontoid process, 7 '6 in. Extreme breadth of anterior 

 articular surface, 5'7 in. Length of spinal platform, 5-2 in. Height of spinal 

 canal, posteriorly, 17 in. Breadth of spinal canal, posteriorly, 1'7 in. 



