PLATE I. 



Fig. Page 



1. Ophthalmosaunis icenicus, Seeley ; transverse section of root of tooth : 



magnified twelve diameters. [R. 3013.] 36 



2. Ditto ; transverse section of crown of tooth : magnified twelve diameters. 



[R. 3013.] 36 



3. Ditto ; transverse section across the base of the crown of tooth : magnified 



twelve diameters. [R. 3013.] 36 



4, 5, 6. Ditto ; teeth : nat. size. [R. 3013.] 36 



7, 8. Ditto ; anterior ends of the rami of the mandible of a young individual 



with teeth in situ : nat. size. [R. 2181.] 36 



9. Ditto ; three sclerotic plates : one-half nat. size. [R. 2740.] 31 



10. Ditto ; section across junction of two sclerotic plates showing the inter- 



locking suture : nat. size. [R. 2740.] 31 



11. Ditto ; left quadrate, outer face : two-thirds nat. size. 



[Type specimen, R. 2133.] 18 



12. Ditto ; left stapes, from front : two-thirds nat. size. 



[Type specimen, R, 2133. J 11 



13. Ditto ; basioccipital, from above : two-thirds nat. size. 



[Type specimen, R. 2133.] 5 



14. Ditto ; basioccipital, from behind : two-tliirds nat. size. 



[Type specimen, R. 2133.] 5 



15. Ditto ; left opisthotic from above : two-thirds nat. size. 



[Type specimen, R 2133.] 9 



art., articular surface of quadrate. i p.c, pulp-cavity of tooth. 



boc.f., facet for basioccipital. 



c, cement. 

 cond., occipital condyle. 

 d., dentine. 

 e., enamel. 

 exo.f., facet for exoccipital. 

 Ji.c, channel for horizontal semicircular canal, 

 n.c, floor of neural canal. 

 op.f., facet for opisthotic. 



p.e.a., postero-exterua! angle of quadrate. 

 p.v.c, channel for posterior vertical semicircular 

 canal, 

 q.f., facet for quadrate. 

 q.j.f., facet for quadrato-jugaJ. 

 r., ridge for muscle-attachment. 

 s., suture between sclerotic plates, 

 sj./., facet for squamosal. 

 st.f., facet for stapes. 



