PLATE XXIII. 



Fig. Page. 



1. Osmeroides lewesiensis (Mantell) ; imperfect fish, ventral aspect, four 



fifths nat. size. — Turonian zone; Southover, Lewes, Sussex. B. M. 

 no. P. 7188. a., base of anal fin; d., dentary; gu., gular plate; 

 mx., maxilla; op., operculum; pet., pectoral fins; pic, pelvic fins; 

 smx. 2, posterior supramaxilla ; sop., suboperculum. 114. 



2. Ditto ; head, left lateral aspect, with upper view of rostral region. — 



Turonian zone ; Lewes. Mantell Collection (B. M. no. 429G). ao., 

 antorbital ; br., branchiostegal rays; -eth., mesethmoid ; fr., frontal; 

 po., postorbital cheek-plate; pop., preopercuhim ; qu., quadrate; 

 other letters as in fig. 1. 115. 



3. Ditto ; cranial roof, lacking ethmoid region, upper aspect. — Ibid. 



Mantell Collection (B. M. no. 4295). fr., frontal; ]><(., parietal; 



st., supratemporal ; spo., supraorbital; sq., squamosal. 115. 



4. Ditto; right quadrate (qu.), metapterygoid (mpt.), ectopterygoid (eapt.), 



and symplectic (sym.), outer aspect. — Chalk ; Kent. Harford 

 Collection (B. M. no. P. 5680). 116. 



5. Ditto; left maxilla (mx.), with supramaxillas (smx. 1, 2), outer aspect, 



and (5 a) anterior end of dentaries, oral aspect. — Turonian zone ; 

 Lewes. Capron Collection (B. M. no. 49891). 116. 



6. Ditto; right mandibular ramus, outer aspect. — Ibid. Mantell Collec- 



tion (B. M. no. 4296). ag., articulo-angular; d., dentary. 116. 



7. Ditto ; two caudal vertebral centra, lateral aspect, three halves nat. 



size.— Ibid. Capron Collection (B. M. no. 49892). 117. 



8. Ditto ; scale, three times nat. size. — Zone of Ilolaster subglobosus ; 



Dorking, Surrey. Capron Collection (B. M. no. 49894). 117. 



9. Osmeroides levin, A. S.Woodward; imperfect fish, dorsal aspect. Type 



specimen. — Zone of Ilolaster subglobosus; Burham, Kent. Harford 

 Collection (B. M no. P. 5681). do., dorsal fin; fr., frontal; pa., 

 parietal; sq., squamosal. 118. 



10. Ditto; head, upper aspect. — Ibid. Egerton Collection (B. M. no. P. 



1854). op., operculum; pit., post-temporal; socc, supraoccipital ; 

 spo., supraorbital. 118. 



11. Ditto; head with opercular apparatus, left lateral aspect. — Zone of 



Ilolaster subglobosus ; Lewes. Capron Collection (B. M. no. 49903). 

 ag., articulo-angular; br., branchiostegal rays; d., dentary; gu., 

 gular plate ; iop., interoperculum ; mx., maxilla ; op., operculum ; 

 po., postorbital ; pop., preopercuhim ; sop., suboperculum. 118. 



Unless otherwise stated, the figures are of the natural size. 



