238 FOSSIL FISHES OF THE ENGLISH CHALK. 



with a sixth beaded ridge behind, and all but the foremost curve forwards at the 

 ends. As in the median tooth, its granulated margin is of considerable width. 

 It is wider in proportion to its length than any of the three inner teeth shown in 

 Text-fig. 74, though it agrees in relative size with the latter. The teeth regarded 

 as belonging to the inner paired row in the Wantage specimen, however, are 

 much smaller. An outer lateral tooth (fig. 3) exhibits oblique distortion, and is 

 crossed by only five ridges. Other typical lateral teeth, either upper or lower, 

 are figured by Agassiz, /"///. clt., pi. xxva, figs. 1-4. 



As shown by an associated set from Lewes in the Mantell Collection, the small 

 upper median teeth are oblong in shape, with a truncated hinder border and a 

 rounded anterior border (LI. L, fig. i»). Their gently tumid coronal face is for 

 the most part rugose or granulated, the raised portion being very small, confined 

 to the middle of the anterior half and crossed by three or four coarse ridges. 

 The posterior granulation forms faint ridges and grooves radiating from this 

 raised portion to the truncated border. The teeth ascribed to the first or inner 

 paired row are usually nearly square, and very variable in the coarseness and 

 number of their transverse ridges. One small specimen (PI. L, fig. 10) has the 

 hinder three of its six transverse ridges sharply curved forwards at the ends. 

 A larger specimen with only five transverse ridges (fig. 7) occurs associated with 

 the coarsely-ridged lower median tooth shown in fig. G. A shorter tooth of the 

 same width as the latter, also with five transverse ridges, is the type specimen 

 of the so-called V. paucisulcatus. Still larger teeth, probably of the same row, 

 are sometimes very coarsely marked with only six transverse ridges (fig. 11), 

 while others are more finely marked with nine or even ten ridges (fig. 12). The 

 teeth of the other paired rows in the upper jaw are considerably smaller, and are 

 not really distinguishable from those of the lower jaw. One found with the 

 originals of figs. G, 7, is shown in fig. 8. 



The principal teeth of V. latissimus resemble those of other species in some- 

 times exhibiting considerable variations in their length compared with their 

 width. This is especially well shown in the upper inner paired row of Text- 

 fig. 75, where the shortest tooth is wider than long and only three quarters as 

 long as the longest tooth. It is therefore justifiable to regard as belonging to 

 a variety of this species the associated set of upper teeth, of which four are shown 

 in PI. L, figs. 13 — 1G. The tooth of the inner paired row (fig. 13) is about two 

 thirds as long as wide, and crossed by seven transverse ridges, of which the ends 

 curve forwards in rows of granules over the narrow granulated area. Its deter- 

 mination as an upper inner tooth is confirmed by the presence of a well-marked 

 facette of wear at one end, with no trace of wearing at the other end. The outer 

 lateral teeth (figs. 14 — 1G) progressively decrease in size and are crossed by six 

 ridges. 



Horizons and Localities. — Turonian zones : neighbourhood of Lewes and East- 



