PLATE XXVI. 
Holcodiscus Faku. 
Fig. i. Lateral view of large specimen. Natural size. 
,, 2. Suture of large specimen. Natural size. 
Holcodiscus afvicanus. 
,, 3. Lateral view. Natural size. 
,, 4. Half outline of transverse section at diameter of 40 mm. 
Natural size. 
,, 5. Suture. Natural size. 
