PLATE XXX. 



Fig. Page. 



1. Belonostomus ductus, Agassiz; portions of upper and lower jaws, right 



side view. — Zone of Holaster subglobosus ; Dover, Kent. B. M. 

 no. P. 8632. d., dentary; ps., presjmphysial bone; r., rostrum; 

 x., undetermined tooth-bearing bone. 143. 



2. Ditto ; rostrum, left side view, with tooth (2 a) enlarged four times. — 



Turonian zone; Whyteleafe, Surrey. Miss Caroline Birley's 

 Collection (B. M. no. P. 10521). 143. 



3. Ditto ; mandible, wanting hinder end, upper view, two thirds nat. size, 



and (3 (/) part of right side view, nat. size, with (3 /;) some splenial 

 teeth enlarged ten times. — Chalk ; Brighton, Sussex. Willett 

 Collection no. 91, Brighton Museum. <!., dentary ; ps., presyni- 

 physial bone ; spl., splenial. 144. 



4. Ditto; anterior portion of mandible, left side view, with (4a) transverse 



section of presymphysial bone, twice nat. size, and (4 l>) a median 

 tooth, four times nat. size. — Ibid. Willett Collection no. 92, 

 Brighton Museum. Letters as in fig. 3. 144. 



5. Ditto ; broken base of lower median tooth, showing vertical fluting, 



four times nat. size.— English Chalk. B. M. no. P. 10448. 144. 



0. Ditto; scales of flank of the type specimen. — Turonian zone; Lewes, 



Sussex. Mantell Collection (B. M. no. 4266). 145. 



7. Ditto ; dorsal scale, showing ornament, four times nat. size. — English 



Chalk. B. M. no. P. 10620. 145. 



8. Diagram of arrangement of flank-scales of Belonostomus. 



Unless otherwise stated, figures are of the natural size. 



