1 68 



ELOPIFORM FISHES 



soc 



ot s.c 



exo 



Fig. 86. Albula oweni (Owen). Neurocranium, posterior view of dorsal half. 



From B.M.N. Ff. 39439. 



Holotype. Parasphenoid ; in the collection of the Royal College of Surgeons, 

 London. From the London Clay (Ypresian) of Sheppey, Kent, England. 



Material. B.M.N.H. 39439, P.9158, and various isolated teeth, teeth with sup- 

 porting bones, and a decaying specimen of the viscerocranium, all from the London 

 Clay (Ypresian) of Sheppey. Postcranial remains are unknown. 



Horizon and locality. Lower Eocene of S.E. England, France, Belgium and 

 N. Africa, and Middle Eocene of Belgium. 



Descriptive remarks. Woodward (1901) distinguished A. oweni from A. vulpes 

 by the relative lengths of snout to frontal notch in the two species. The frontal 

 notch in Albula occurs at the hind margin of the lateral ethmoid and is thus compar- 

 able with the preorbital distance, a feature used here. 



Several other neurocranial features distinguish A. oweni from the type-species. 



In dorsal view the skull roof of A. oweni shows a marked median frontal depression 

 at the level of the autosphenotic spine. Such a depression is suggested in A. 

 vulpes, but it never attains the same relative proportions. Perhaps its development 

 is a consequence of absolute size, this being greater in A. oweni. Above the orbit, 

 the frontals exhibit a rugose ornamentation not seen in the extant species. Such 

 ornament is seen in the Osmeroididae where it is often (Osmeroides lewesiensis) more 

 extensive. Apart from these minor differences the skull roof of A. oweni (Text-fig. 

 85) is very similar to that of A. vulpes (Text-fig. 75). 



The posterior neurocranial wall shows well-developed sub-epiotic fossae (an 

 albuloid feature) which are bordered medially by stout vertical ridges (a feature 

 typical of the osmeroidids but not found in A. vulpes). The supraoccipital of A. 

 oweni (Text-fig. 86) is of different proportions to that of A. vulpes and there is a small 

 interspace between the supraoccipital and exoccipitals. Neither an ' isolated 



