ACRODUS. 



15 



and gently rounded, marked by a longitudinal median wrinkle ; the laterally 

 directed wrinkles are short, unusually stout, and marginal, but few tapering and 

 extending to the middle line. 



Description of Specimens. — The type tooth from Brixton, Isle of Wight, is 

 elongate-ovoid in shape, about twice as long as wide, probably belonging to one 

 of the principal lateral rows. A second specimen, obtained by the Rev. William 

 Fox from the same locality, is slightly longer and more attenuated at the extremi- 

 ties. A somewhat larger tooth from Brook, of nearly similar shape, broken at 

 one end and naturally curved at the other tapering end, is shown enlarged five 



Fig. 6.—Arrodus anningiee, Agassiz ; dentition in matrix, almost nndistiirhed, nat. size. — Lower Lias ; 

 Lyme Eegis, Dorset. British Museum, no. 39925. After E. C. H. Day, Geol. Mag., vol. i (1864), 

 \)\. iii. 



times in PI. II, fig, 15. This is completely unworn, and exhibits well the longi- 

 tudinal median wn-inkle, with the few and thick lateral wrinkles, which taper 

 towards the middle line but rarely reach it. Another specimen of more regular 

 shape (PL II, fig. 16), with almost equally well preserved wrinkles, also belongs to 

 a principal row. The relatively short and wide teeth wdiicli may be referred to 

 the rows near the symphysis, such as the original of PL II, fig. 17, do not exhibit 

 any trace of lateral elevations or denticles. Other teeth, more irregular in shape 

 and wrinkling, probably belong to the hinder part of the jaw (PL II, fig. 18). 



Horizon and Localities. — Wealden : Brixton and Brook, Isle of Wight ; 

 Hastings and Bexhill, Sussex. Waterworn specimens of nearly similar teeth have 

 also been found in the Lower Greensand of Godalming, Surrey. 



