352 PLKISTOCRNE GEOLOGY OF THE THAMES VAT.LEY. 



Esox lucius, Linn. (Pike). A number of teeth of various 

 sizes, the largest measuring 13.0 mm. or more in length, and 

 having the compressed crown with sharp edges, so characteristic 

 of the pike, are believed to represent this species at Grays. The 

 same form has long been known to occur at Ilford and in beds of 

 similar age elsewhere, as well as in the Norfolk Forest Bed. 



Leuciscus. Several pharyngeal bones and numerous 

 isolated teeth of Cyprinoid fishes are without doubt referable to 

 this genus ; but while some of the specimens can be definitely 

 assigned to species, most of the isolated teeth can only be 

 generically named or at best placed in species provisionally. 



Leuciscus rutilus, Linn. (Roach). Two pharyngeal 

 bones, each with a single row of teeth and these of the forms 

 found in the Roach, supply as good evidence as could be 

 expected of the presence of this species at Grays ; and it is 

 almost certain that the greater number of the isolated teeth also 

 belong to this form, which has been recognised in other British 

 Pleistocene beds and also in the Norfolk Forest Bed. 



Leuciscus vulgaris, Flem. (Dace). Four small pharyngeal 

 bones, each with two row'S of teeth, which are comparatively 

 long and with somewhat hooked extremities, are believed to be 

 rightly placed with L. vulgaris, and certain of the isolated teeth 

 probably belong here also. I am not aware that this species has 

 before been found in Pleistocene beds. 



Leuciscus erythrophthalmus, Linn. (Rudd). A single 

 isolated crown, which is long, slender, curved and strongly 

 crenulated, is the only specimen which can at present be placed 

 in this species. Evidence of the Rudd was found in the Norfolk 

 Forest Bed and it has also been met with in Pleistocene beds at 

 Hitchin. 



Anguilla ? anguilla ? Linn. (Eel). A single imperfect 

 vertebra has the neural arch strongly developed and forming a 

 bony tube as long as the centrum itself. A similar condition of 

 the neural arch is found m certain of the vertebrae of the common 

 Eel, and it seems probable that our specimen represents that 

 species which has not hitherto been recognized as a fossil. It 

 may seem hazardous to record a species, even with doubt, upon 

 such slender evidence ; but I feel justified in so doing in order 

 that attention may be directed to the possible occurrence and so 

 further evidence be sought for. 



