566 
DR. A. GUNTHER’S DESCRIPTION OF CERATODUS. 
s. Suspensory pedicle. 
ss. Suprascapula. 
sy. Symphysis mandibulee. 
d. Vomerine tooth. 
w. Foramen for nervus vagus. 
Fig. 3. Lower jaw, viewed from the oral cavity; on the left side the soft parts are pre- 
served ; on the right the osseous and cartilaginous parts are dissected. 
ar. Articulary. 
ar'. Large foramen perforating the lower jaw from below. 
dt. Dentary. 
la. Labial cartilage. 
to. Tongue. 
Fig. 4. Vertical section through a ramus of the mandible, of the natural size. The 
centre is entirely cartilaginous, the sides being covered by the articulary 
(ar) and dentary (dt). a is the section through the tooth which is anchylosed 
to the dentary, hut separated from the articulary by connective tissue (ct ) ; 
pulp-cavity — j)c. 
Fig. 5. The same magnified, without the tooth. This figure shows the porous nature 
of the bones, ct is a strip of connective tissue between the central cartilage 
and articulary. 
Fig. 6. Bone-corpuscles of articulary. 
Fig. 7. Cartilage-cells from the margin of mandibulary cartilage. 
Fig. 8. Cartilage-cells from its centre. 
PLATE XXXVI. 
Fig. 1. Termination of the notochord, and its junction with the skull ; a vertical longi- 
tudinal section, magn. 216. 
n. Cartilage of the notochord. 
c. Cartilage of the base of the skull. 
Fig. 2. Scapular arch (right half), anterior view, of the natural size. 
Fig. 3. The same, posterior view. 
a. Median cartilage (right half). 
b. Humeral cartilage. 
c. Condyle for the articulation of the fore arm. 
d. Coracoid (scapula). 
e. Suprascapula. 
Fig. 4. Pelvis (outer view), with right ventral paddle ; nat. size. 
a. Fibrous sheath of process slit open. 
Fig. 5. Longitudinal section through the pelvis, to show the cavity (b). 
Fig. 6. Pelvis of Protopterus, of the natural size, for comparison with fig. 4. 
