Fo.'isil Teeth of Mjliobatis. 45 



1833-43. Mtfliohatis suiuraUs, Agassiz, torn. cit. p. 322, pi. xlvi. figs. 12- 



16. 

 1833^3. Myliohatis nitidns, Agassiz, torn. cit. p. 325. 

 1847. Myliohatis striatus^ Owen, Ann. & Mag. Nat. Hist. [1] vol. xix. 



pp. 25-27, woodcut. 



The well-known species of Sheppey is readily recognized 

 by the flat, comparatively thin crown of the lower dentition 

 and the broad, diamond- shaped lateral teeth ; but there is 

 little to add to the original descriptions of Agassiz, who made 

 known both the upper and lower jaws. The following table, 

 however, may be interesting, as illustrating some of the 

 changes in the relative dimensions of the median teeth corre- 

 sponding to an increase in absolute size. Specimen no. VII., 

 as already mentioned (p. 39), exhibits irregularity of growth,, 

 and probably belongs to an unusually large individual. 



Lower Dentition o/Myliobatis toliapicus. 



Length of 

 Median Plate. 

 00035 

 0-004 

 0-005 

 0005 

 0005 

 0-0055 

 0-007 



It may also be added that, so far as the type specimen of 

 Agassiz, M. nitidus^ will allow of determination, this fossil 

 is referable to the upper jaw of the present species. The 

 name, however, was published without definition, and so has 

 not been employed in the nomenclature of other fossils. The 

 specimen consists of a connected series of six upper median 

 teeth, from the London Clay of Slieppey, and is now preserved 

 in the British Museum in the Egerton Collection (no. P. 528). 

 Each dental plate has a breadth of 0*024 and measures 0*0045 

 in length, and all the lateral teeth are destroyed. 



Range. Barton and Bracklesham Beds | London Clay, 



Myliohatis latidens., sp. nov. (PI. L figs. 11, 12.) 



A hitherto unrecognized species appears to be indicated by 

 some small examples of the lower dentition from Bracklesham^ 

 and with these may also be associated one or two series of 

 upper median teeth from the same locality. The originals of 

 tigs. 11 and 12 may be regarded as typical, and they are 



