PROFESSOR, OWEN ON THE MEGATHERIUM. 
589 
Description of the Plates. 
All the figures, save where otherwise expressed, are one-fourth the natural size. 
PLATE XXL 
Fig. 1. Side view of the skull of the Megatherium. 
Fig. 2. Inner side view of the mandible and of the section of the symphysis. 
PLATE XXII. 
Fig. 1. The opposite and more mutilated side view of the same skull, showing the 
surface of the temporal fossa. 
Fig. 2. Upper view of the same skull. 
PLATE XXIII. 
Fig. 1. Back view of the same skull. 
Fig. 2. Front view of the same skull. 
Fig. 3. Back view of the mandible. 
Fig. 4. Front view of the same mandible. 
PLATE XXIV. 
Base view, natural size, of the same skull, and grinding surface of the upper teeth. 
PLATE XXV. 
Fig. 1. Upper view of the mandible, and grinding surface of the lower teeth. 
Fig. 2. Side view of the mandible. 
PLATE XXVI. 
Fig. 1. The second upper molar tooth: — natural size. 
Fig. 2. Longitudinal section of the alveolar part of the upper jaw and of the five 
upper molars, in situ: — three-fourths of the natural size. 
Fig. 3. Transverse section of a portion of a molar tooth of the Megatherium : — mag- 
nified 500 linear diameters. 
The letters and ciphers on the several figures are explained in the text. 
