FOSSIL AND RECENT in 



taken as representing the mid-body level then the total lateral line count must have 

 been about 80 (Woodward 1901 : fig. 2, indicates 87). The transverse count is 7/6 

 at both the occiput and the dorsal fin. 



The scales have a characteristic shape and together with those of 0. levis are dis- 

 tinctive among remains of the English Chalk fish fauna. Each scale is large, 

 angular anteriorly but smoothly rounded posteriorly. The exposed portion is 

 marked by fine tuberculations set in an apparently irregular fashion. The covered 

 portion bears many smaller tuberculations and these are set in a radial pattern. 

 Fine circuli are arranged concentrically around a central nucleus. The majority of 

 the anterior body scales are marked by 3-8 (mode 5) radii which produce a scalloped 

 margin anteriorly. Towards the tail the scales appear more rounded and do not 

 bear radii. Lateral line scales are marked by a longitudinal ridge which terminates 

 as a notch on the posterior margin of the scale. 



Osmeroides levis Woodward 

 (Text-fig. 54) 



1895 Aulolepis typus Agassiz ; Woodward : 660, pi. 43, figs. 2, 3, 5 (errore). 



1900 Osmeroides sp. ; Woodward : 325. 



1 90 1 Osmeroides levis Woodward : 15. 



1907 Osmeroides levis Woodward; Woodward : 118, pi. 23, figs. 9-11. 



Diagnosis (emended). Osmeroides reaching a maximum length of 200 mm. 

 Length of cranium not exceeding twice its maximum width at the sphenotic region. 

 Parietals as long as wide. Dermal skull bones smooth, ornamented only by weakly 

 developed radiating ridges. Interorbital septum partially ossified. Parasphenoid 

 ending beneath mid-otic region. Quadrate/mandibular articulation beneath middle 

 of orbit. Branchiostegal rays smooth, exact number not known but not less than 

 15. Vertebrae, dorsal fin and scales as in the type-species. 



Holotype. B.M.N.H. P. 5681, from the Upper Cenomanian (Holaster subglobosus 

 zone) of Burham, Kent, England. 



Material. The holotype and the following B.M.N.H . specimens ; 49903 

 (paratype), P. 1854 (part and counterpart), P. 36204. The last specimen was prepared 

 in acid by Dr C. Patterson. All specimens are from the Upper Cenomanian of 

 S.E. England. 



Remarks. 0. levis is both rarer and more restricted in time than the type-species. 

 Although the specimens are not accompanied by horizon data the matrix in which 

 they are embedded is easily identifiable as having the lithology of the Holaster 

 subglobosus zone, and is therefore of Upper Cenomanian age. 



Other than the cranium very little is known of the anatomy. However, sufficient 

 evidence remains to indicate that 0. levis is very closely related to the type-species. 



Woodward (1907) noted the following differences between 0. levis and the type- 

 species. The head and opercular apparatus occupy one-third of the standard length 

 (taken in this instance as the distance between the snout and the caudal peduncle), 

 whereas the head and opercular apparatus are relatively shorter in the type-species. 



