312 DK. E. RA.Y LANKESTER ON OKAPIA. 



PLATE XXXI. 



Fif^. 1. V'icw t'roni above of" the smaller of the two skulls (that wliich does not belon>^ 

 to the skin). Drawn of about half the natural size. The actual measurement 

 of the specimen is : — from the occipital margin to the free end of the nasals, 

 ol2 mm. ; from the occipital margin to the free end of the prsemaxillaries, 

 075 mm. — Reference letters: a, supraorbital tumescence of the frontal bone 

 (site of the future ossicusp or bony liorn-core) ; h, the right pricmaxillary 

 bone ; c, the pra3laci ymnl vacuity. 



Fig. 2. View from above of the larger of the two skulls (that which belongs to the 

 skin and lower jaw). Drawn of about half the natural size. The actual 

 measurement of the specimen is : — from the occipital margin to the free end 

 of the nasals, 375 mm. — Reference letters: «, supraorbital tumescence of the 

 frontal bone (site of the future ossicusp or bony horn-core) ; h, the left 

 preema-xillary, absent in the specimen and drawn here of a lighter tint ; c, the 

 praelacrymal vacuity ; rf, the median tumescence at the base of the nasal 

 bones (see in this connection the profile view of the smaller skull in 

 Plate XXXII.); c, the parietal bones; the fronto-parietal suture is well- 

 marked, but the interparietal suture is already obliterated in the smaller skull 

 as well as in this ; f, the emarginated occipital ridge. 



Fig. 3. The anterior group of teeth of the lower jaw belonging to the larger skull. 

 The teeth are drawn as seen from above, and of the natural size. From the 

 outer margin of the right canine to the outer margin of the left the measure- 

 ment is 41 mm. The six incisors are those of the permanent set ; the canines 

 are the deciduous ones, not yet replaced. — Reference letters : del, left 

 deciduous canine ; dcr, right deciduous canine ; jii, pi, the six permanent 

 incisors. 



Fig. 4. The right permanent canine, obtained by cutting into the bone below the 

 deciduous canine ; inner (adoral) face. One-tenth larger than natural size. 



Fig. 5. Outer (aboral) face of the same tooth as that drawn in fig. 4. 



Fig. 6. The left deciduous canine, drawn so as to show the outer (aboral) surface. One- 

 tenth larger than natural size. 



Fig. 7. Crown of anterior deciduous molar of the right lower series (marked dm^) seen 

 from above. Natural size. 



Fig. 8. Crown of the second (counting the more anterior as the first) deciduous molar 

 of the right lower series (marked dm^) seen from above. Natural size. 



Fig. 9. Crown of the third deciduous molar of the right lower series (marked dm') 

 seen from above. Natural size. 



Fig. 10. The crowns of the three non-successional or true molars of the right lower 

 series seen from above : m^, anterior true molar ; m^, second true molar ; m^, 

 third true molar. 



