PLATE XIX. 



Fig. Page. 



1. Ctenothrissa microcephala (Agassiz); trunk with remains of fins, left 



lateral aspect. — Zone of Holaster subglobosus; Hailing, Kent. B. M. 

 no. P. 9G5G. a., anal fin; c, caudal fin; do., dorsal fin; plv., pelvic 

 fin ; v., rib. 84. 



2. Ditto; head, etc., right lateral aspect, with right premaxilla (2a), outer 



aspect, enlarged three times. — Zone of Holaster subglobosus ; Arundel, 

 Sussex. Capron Collection (B. M. no. 49884). el., clavicle; d., 

 dentary ; ioj)., interoperculum ; mx., maxilla; op., operculum; pet., 

 pectoral fin ; pmx., premaxilla ; pop., preoperculum ; ptt., post- 

 temporal ; scl., supraclavicle ; smx. 1, 2., anterior and posterior supra- 

 maxilla. 84. 



3. Aulolepis typus, Agassiz ; left lateral aspect of fish, incomplete dorsally, 



with cranial roof (3 a), and some scales (3 b) three times nat. size. 

 — From a Turonian zone ; Southeram, Lewes. Forbes Young 

 Collection (Woodwardian Museum, Cambridge), a., anal fin; ao., 

 antorbital ; c, caudal fin ; el., clavicle ; <!., dentary ; eth., mes- 

 ethmoid ; fr., frontal ; mx., maxilla ; op., operculum; pa., parietal; 

 pet, pectoral fin; ph., pelvic fin; pop., preoperculum; smx. 1, 2., 

 anterior and posterior supramaxilla ; socc, supraoccipital ; ,9^., squa- 

 mosal or pterotic or both. 86. 



4. Ditto; four scales of lateral line, three times nat. size. — Zone of 



Holaster subglobosus ; Dorking, Surrey. B. M. no. 36097. 87. 



5. Ichthyodectes sp. ; hinder portion of cranium, left lateral aspect and also 



(5 a) left infero-lateral aspect. — Zone of Holaster subglobosus ; Blue 

 Bell Hill, Burham, Kent. S. J. Hawkins Collection (B. M. no. P. 

 9046). bore., basioccipital ; epo., epiotic; fo., fossa in side of otic 

 region; Jr., frontal; Jim., hyomandibular faeette; opo., opisthotic ; 

 //"., parietal; ]>!■<>., pro-otic; ptf., postfrontal (sphenotic) ; pto., 

 pterotic; socc, supraoccipital. 93. 



G. Ichthyodectes minor (Egerton) ; premaxilla, outer aspect, with two lateral 

 teeth imperfect. — Chalk ; Kent. Mrs. Smith's Collection (B. M. no. 

 49086). 96. 



All the figures, except 2 a, 3 b, 4, of the natural size. 



