98 PROFESSOR OWEN ON THE AYE- AYE. 



PLATE XVII, 

 Back view of the same specimen : half the natural size. 



PLATE XVIII. 



View of the head in profile, and of the fore limbs, of the male Aye-aye : natural size. 



PLATE XIX. 



Skeleton of the male Aye-aye : natural size. The letters and numbers are explained 

 in the text. 



PLATE XX. 



Skull, Teeth, and Hyoid Arch of the Male Aye-aye. 



Fig. 1. Upper surface of skull. 



Fig. 2. Under surface or base of cranium. 



Fig. 3. Upper view of mandible. 



Fig. 4. Front view of skull. 



Fig. 5. Upper view of cranial cavity. 



Fig. 6. Side view of cranial and nasal cavities. 



Fig. 7. Inner side of mandibular ramus. 



Fig. 8. Teeth of left maxilla (upper jaw), in situ, with roots exposed. 



Fig. 9. Outer side of mandibular ramus, with the base of incisor exposed, and the 



three molars added above, with the roots exposed. 

 Fig. 10. Grinding surface of upper and lower molars of the right side : magnified. 



In the figures showing the teeth, — i, incisor ; e, enamel ; d, dentine ; p, pulp ; 



p 4, last premolar, fourth of the typical series, retained in the upper jaw ; 



m 1 , first molar ; m 2, second molar ; m 3, third molar. 

 Fig. 11. Malleus: natural size. 

 Fig. 12. Incus: natural size. Figures of these ' ossicula auditus,' magnified, are given 



below. 

 Fig. 13. Side view of hyoid arch : 41, basihyal ; «, epihyal ; 33, ceratohyal ; ss, stylohyal ; 



46, thyrohyal. 

 The following are the parts indicated by letters in the figures of the skull : — 



a. Precondyloid foramen. 



b. Jugular foramen. 



c. Internal auditory foramen. 



