112 PISCES. 



RAJA, sp. 

 PLATE IX., FIGS. 2 la, b. 



Two fish defences in the Museum of Practical Geology evidently 

 of the same nature as those of R. clavata, but differing in character, 

 are provisionally referred to this genus. One of them is from the 

 Nodule-bed of the Red Crag at Boyton, and the other is from the 

 Coralline Crag of Gedgrave, the latter being the one now to be 

 described. The basal plate is irregular in form, with the margin 

 folded and crenulated ; rising gradually towards the middle it 

 becomes smooth and then forms a strong curved denticle, which 

 is placed towards the broader end of the plate. There is no central 

 depression or concentric lines on the upper surface as in most of 

 the defences of R. clavata, and the under portion is hollowed, 

 the cavity extending into the denticle. 



The defences of Raja radiata somewhat resemble this fossil, 

 but they are more star-like, the radial ridges being strongest 

 towards the centre. 



It may be that these Crag defences do not really belong to Raja, 

 but to some species of Trygon ; I have not, however, been successful 

 in identifying them definitely, and therefore prefer not to introduce 

 another genus without better evidence. 



Genus PEISTIS, Latham. 



Portions of rostral teeth of Pristis from the Red Crag Nodule- 

 bed of Woodbridge are in the British Museum, but have probably 

 been derived from beds of Eocene age. 



Genus SftUATINA, Dumeril. 

 PLATE IX., Figs. 11 a, b, c. 



There is in the British Museum a small tooth from the Red 

 Crag Nodule-bed of Suffolk which Mr. A. Smith Woodward 

 (Cat. Foss. Fishes, B. M., Part i, p. 71, 1889) has referred to this 

 genus, but without any specific determination. Mr. E. C. Moor 

 possesses a similar tooth from the same horizon at Little Bealings, 

 near Woodbridge, and there is a third in the York Museum. 

 These teeth have an acute median cusp on a wide basal portion 

 and are without lateral denticles ; but there is a downwardly 

 directed median process of the shining crown on the outside, and 

 a horizontally directed portion on the inside. The root of the 

 tooth forms a plate almost at right angles to the cusp, and on its 

 underside is a depression in which is the vascular foramen. 



