412 Davis — On the Fossil Fish of the Cretaceous Formations of Scandinavia. 



Corax lindstromi, Davis, sp. nov. 

 (PI. XLIL, figs. 3-11.) 



Teeth of medium size, varying much in height and breadth of crown, but all 

 possessed of an arched anterior margin, extending far down, and enveloping the 

 base or root, and a more or less deep indent of the posterior margin. A large 

 example has a breadth across the base of the crown of 0'022 m. ; the height of the 

 crown on the external surface is 0"012m., and on the internal one 0'009 m. The 

 size varies to specimens having only one-third these measurements. The external 

 surface of the crown is slightly convex in the median part, flat towards the 

 margins ; slight folds in the enamel rise from the base, and disappear higher on 

 the crown. Internal surface convex, with delicate, broad folds near the base. 

 Line dividing the crown from the base deeply arched upwards on internal surface, 

 less so on the external one. Anterior margin boldly arched, and extending over 

 the root. Posterior margin straight, or with a slightly sigmoidal curvature, on 

 upi^er part ; the lower part extends thence more or less horizontally, forming a 

 deep indent, at an angle varying from a right-angle to one which is obtuse. The 

 margins are uniformly and finely serrated over their whole length ; the apex 

 of the crown is acuminate, the root is large, equal in breadth to the crown, flat 

 on the external surface, convex on the internal one, inferior surface slightly 

 concave. 



The study of the large series of specimens of the genus Corax in the British 

 Museum has induced Mr. A. Smith Woodward to reduce the number of species to 

 three, viz. Corax pristodontus, Ag., C. falcatus, Ag,, and C. affinis, Ag. The last 

 is a small species, the principal teeth of which have a much elevated, slender 

 crown, with a notch on both the posterior and anterior margin, producing a broad 

 posterior, and a narrow anterior denticle. Corax falcatus is medium sized ; the 

 crown is elevated, not so much so as in C. affinis ; the anterior coronal margin is 

 arched, but not so much as in the Corax pristodontus ; the posterior coronal margin 

 is more or less deeply notched, and the base of the enamel on the external sur- 

 face is comparatively straight. Corax pristodontus has a very broad base, a large 

 tooth, has little or no indentation on the posterior margin, and the anterior 

 margin of the crown is prolonged for a considerable distance over the root ; the 

 base of the crown on the external surface being thus rendered much arched, a 

 feature not very well exhibited in the specimens figured by Agassiz ("Poiss. Foss.," 

 vol. iii., pi. XXVI., figs. 10—13). The teeth now described from the Lower 

 Senonian strata of Ifo and Oretorp appear to occupy an intermediate position 



