DESCKIPTION OF PLATES. 11 



19- in. Height to anterior margin of alveolus, 8 - in. Greatest thickness behind, 

 6 - o in. Interval between teeth in front, 3 - 6 in. Interval behind, 5 - 6 in. Length 

 of right molar, ITS in. Width of right molar in front, 3- in. Width behind, 2 - 8 in. 



Fig. 8. — E. planifrons. Superb specimen of left half lower jaw, 

 entire. The coronoid crescent slopes downwards from the condyle. 

 Crown of the tooth very Ioav. Seven last plates of tooth only remain ; 

 great thickness of enamel and abundant cement, and mesial expansion ; 

 enamel plates projecting. Proved to be E. planifrons by the distance 

 between the plates, the very low crown, thick enamel, and two mental 

 foramina. — B.M. 



Extreme length of jaw, 24-2 in. Height of alveolar margin, 7'5 in. Height of 

 ascending ramus to top of the condyle, 20 - 2 in. Width of ascending ramus from 

 coronoid margin to posterior edge, 10 - 5 in. Greatest thickness, 6-1 in. Transverse 

 measurement of condyle, 4 - 2 in. Length of molar, 10 - in. Width of molar at 

 middle, 3-6 in. 



Fig. 4. — E. planifrons. Is a most remarkable fragment of the last 

 molar, upper jaw, right side, taken out of a palate in H. F.'s collection. 

 It is figured to show how diversified the species may be, and also the 

 dedalian line of flexure. 



Length of fragment, 5"4 in. Width, 2 - 5 in. 



Fig. 5. — Eleplias planifrons. Enormous tooth-fragment, with very 

 thick enamel, low plates, and mesial expansion. This specimen is 

 twice figured (See Plate XVHI. A. fig. 2). It is the last molar, lower 

 jaw, right side. — B.M. 



Length, 105 in. Greatest width, 4 - 2 in. Height of ninth plate, 3 - 5 in. 

 Number of ridges, 9. 



Fig. 6. — Eleplias planifrons. Lower jaw, left side, with first and 

 second (antepenultimate and penultimate) true molars. The first 

 tooth is much worn ; shows about six plates ; enamel transverse with 

 little crimping. The penultimate has nine ridges and a small heel, or 

 eight and a double heel ; the two front ridges barely touched. The 

 ridges have few points, the fourth having only five. ( Fide E. insignis, 

 Plate XVm. fig. 7).— B.M. 



Length of front molar, 6' in. Greatest width, 2-8 in. Length of penultimate, 

 8- in. Width at fourth ridge, 2-8 in. 



Fig. 7. — E. planifrons. Left side of lower jaw, with last molar very' 

 old. All the first half of the grinding ridges worn out. Very great 

 expansion of the plates. Three mental foramina outside. — B.M. 

 Length of molar, 102 in. Greatest width, 4- in. 



Fig. S. — E. planifrons. A magnificent typical specimen, consisting 

 of a fragment of the lower jaw with whole length of penultimate true 

 molar ; the anterior fang exposed ; the three first ridges on this fang 

 gone by wear ; eight other ridges, making eleven ridges and a heel ; 

 enamel very thick ; plates wide apart ; much cement ; few points ; 

 three mental foramina. — B.M. 



Height of jaw to alveolar margin, outer side, 8 - 6 in. Greatest thickness, 

 6-4 in. Length of molar, 12-1 in. Width at fourth ridge, 3-6 in. Greatest 

 width, 3-8 in. 



Fig. 9. — Eleplias planifrons. A fragment of last lower molar, left 

 side, intended to show the large digitations and few points of the 

 species. It has the three last ridges and a heel ; points very distinct, 



