38 CRETACEOUS AND TERTIARY FISH. 



Formation and locality. I have 7 teeth from the marls [Man- 

 asquan formation, K.] at Vincentown (T. M. Bryan), also 2 

 from Delaware (P. Uhler). 



Isurus acuminatus (Morton). 



Squalus sp. Morton. Synop. Org. Rem. Cret. U. S., 1834, P- 3 1 . PI- Il > fig- 



11. New Jersey. 

 Lamina acuminata (Agassiz) Morton, Am. Journ. Sci. Art., XXVIII, 1835, 



p. 277 (name only, based on preceding). 

 Squalus sp. Morton, Synop. Org. Rem. Cret. U. S., 1834, p. 31, PI. 11, fig. 4. 



No locality. 

 Lamma mantelli (Agassiz) Morton, Am. Jourri. Sci. Art., XXVIII, 1835. p. 



277 (name only, based on preceding). 



Teeth moderately robust, compressed, and vary from widely 

 angular to acuminate. Crown slightly curved out toward apex. 

 Outer coronal surface mostly flattened, sometimes a few vertical 

 basal wrinkles, and inner surface moderately and evenly convex. 

 Apex usually deflected slightly to one side. Cutting-edges entire. 

 Sometimes a low, obsolete, broad, basal cusp at one or each side 

 of base, variable. Root short, with usually obtuse edges, outer 

 surface flattened or concave, inner surface moderately Convex, 

 and lower profile a little emarginated. Anterior teeth compara- 

 tively wide, with only a gentle curved crown, and lateral teeth 

 with root much broader than crown, thus forming a sudden basal 

 expansion behind and often anteriorly. Length reaches 40 mm. 



Known only from detached teeth. Although this species is 

 usually known by the specific name mantelli, Agassiz's name acu- 

 minata occurs first on the same page in Morton's work. Mor- 

 ton's figure is rather incomplete, though it shews a basal cusp. 

 His figure of mantelli, though also crude, represents a much 

 larger tooth, and is probably the same as the one Agassiz pub- 

 lishes later. 



Formation and locality. The following examples appear to 

 belong to this species, most all evidently from the Cretaceous 

 marls. They are: 5 imperfect teeth from "New Jersey" (C. C. 

 Abbott), 2 from the same (Burtt), 10 from Monmouth County 

 (W. Cleburne), 1 from the same without donor, 1 from the 

 same (P. D. Knieskern), 5 from the Miocene formation of 



