HIPPOPOTAMUS LIBEKIENSIS. 405 



Measurements of Hip. (Tetraprotodon) Libcriensis. — From occipital crest to 

 anterior margin of incisive bone, 128 in. From ditto to tips of nasals, 11-8 in. 

 Width between posterior borders of orbits, 5 - in. Width between anterior ditto 

 at foramen, 3 p 6 in. Greatest width zygomatic arches (i 3'9), 7"8 in. Width of 

 occiput, 3*1 in. Width of head at contraction (orbit, foramen), 2'5 in. Width of 

 ditto at bulges of canine alveoli, 5 - 25 in. Width of incisives, 3 - in. Height of 

 head to margin of alveolus at suborbital foramen, 3.5 in. Length from occipital 

 crest to suborbital foramen, 7'75 in. Length from ditto to posterior border orbit 

 (postorior orbital foramen), 4 - 75 in. From ditto to anterior border of ditto, 625 

 in. Antoro-posterior diameter orbit, 19 in. Vertical ditto, 24 in. Interval 

 between interior surface of zygomatic arches at point of greatest expansion, 7'6 in. 

 Length of alveolus at margin of molars, 6 - in. Interval between anterior false 

 molar and canine, 0'25 in. From ditto to inner margin alveolus, middle molar, 

 2 - l in. Width of palate between the tusks, 2 - 75 in. Width between the outer 

 incisors, l - 75 in. Width between outer false molars, 2 - in. Width between third 

 false molars, 1"4 in. Length of three posterior true molars, 34 in. Width of 

 forehead between middle of orbits, 3- 75 in. Interval between middle incisors, 1" 

 in. Length of alveolar margin of two incisors (of one side), - 9 in. From anterior 

 margin of orbit to tip of the muzzle, at middle incisor, 7' in. From ditto to crest of 

 occiput, 65 in. Length of nasal bones, 64 in. Depth of nasal opening, 1*75 in. 

 Transverse diameter of nasal opening, 1'75 in. Interval between tips of posterior 

 orbitary processes, l'l in. Transverse diameter of tusk, 1*1 in. Vertical dia- 

 meter of ditto, - S in. Depth of reniform channel, 04 in. Diameter of outer 

 incisor, 4 in. From anterior margin of orbit to orbitary foramen, 1'75 in. 



Lower Jaw. — Extreme width of alveoli of tusks, ±5 in. Interval between 

 canines, 2*8 in. Interval between canine and incisor, - 5 in. Interval between 

 incisors, -8 in. Diameter of left lower incisor, - 55 in. Between tusk and first false 

 molar, - 4 in. Length from posterior margin of condyle to tip of muzzle, 10" in. 

 Length from posterior margin ramus to ditto, 10 - 25 in. Length of symphysis, 2 - 8 

 in. Width of jaw at contraction below third false molar, 375 in. Width behind, 

 in front of niche, 5 - 3 in. Greatest expansion of leafy dilatation below, estimated, 

 90 in. Extreme height from lower margin of expansion to tip of coronoid, 59 in. 

 From anterior margin coronoid to posterior ditto of condyle, 2-5 in. Height of 

 lc^fy expansion to niche in front of condyle, 4'6 in. Height of jaw to margin of 

 alveolus between second and third false molar, 245 in. Height of jaw at last 

 molar, 1-9 in. Width of condyle across. T25 in. Interval between first false 

 molars, 2-6 in. Interval between third false molars, 2-0 in. Length of three pos- 

 terior molars, 3 - 4 in. Length of alveolar border, four false ditto, 345 in. Length 

 of leafy expansion, 3'5 in. 



Hippopotamus comprises two Subgenera, Hexaprotodon, with six in- 

 cisors above and below, and Tetraprotodon, with, reduced incisors, viz. 

 four above and below. Hip. Liberiensis, although it has but two in- 

 cisors in the lower jaw, belongs to the latter subgenus ; the excessive 

 reduction is probably only an individual case of variety, but if proved 

 to be constant the position of the species would not be altered. The 

 succession of the species in the subjoined synoptical table indicates the 

 order of their affinities. No. 1, H. major, is the most divergent form, 

 with short cranium, posterior orbits, great elevation of the sagittal and 

 occipital crests, and excessive elevation of the upper margin of the 

 orbits above the plane of the brow. Next follows //. palwindicus, a 

 true fossil Hippopotamus from India. Then comes H. amphibius, No. 3 

 in the series, of which the French naturalists make two species, H. Ca- 

 pensis and H. Senegalensis. Duvernoy (Comptes Rendus, Oct. 184G) 

 maintains their distinctness, but I regard them as merely varieties. //. 

 Pentlandi (No. 4) is the fossil species which prevails in Sicily, Malta, 

 and Candia. II. annectens (No. 5) is a fossil species from the Nile 



