TKICHIURID^. — Leidy. 121 



species, the localities in which its remains have been found, would prove it to have 

 extended from the green sand period, through the tertiary period, and to have become 

 extinct just prior to the present period. 



The teeth correspond with the largest anterior teeth of both upper and lower jaws of the 

 Barricuda (Sphyraena barricuda,) but indicate a much more powerful and equally vora- 

 cious fish. 



The specimen represented in figures 3 and 4 exhibits well the form of these remarkable 

 teeth. Its crown inverted, with smooth shining enamel, is laterally compressed conical, 

 with an anteroposterior sigmoid flexure in the length. Two-thirds of the posterior border 

 from the point, and the whole of the anterior border are trenchant. The apex is rather 

 abruptly pointed, and appears to be inserted with thicker enamel than the other portion of 

 the crown. 



The root or fang of the tooth presents a remarkable anatomical character in its gradual 

 expansion to the base of attachment to the jaw. It is nearly as long as the crown is quad- 

 rilateral, and slightly unsymmetrical. Its base is divided antero-posteriorly by a broad 

 cleft, deepening in front and behind, and on the outer sides is vertically grooved. 



The teeth of the Ischyrhiza have a cavity in the interior, extending from the fang into 

 the crown, but presenting no communication with the exterior. 



Plate XXV. Fig. 3, Lateral view of a tooth of Ischyrhiza mira, Leidy. 



" 4, Anterior view of the same specimen. 



" 5, Lateral view of another specimen. 



" 6, Anterior view of the same. 



" 7, Base view of the same. 



" 8, Base view of figs. 3 and A. 



Locality No. 3. Ashley beds. 



No. 5. Darlington, (Meiocene?) Museum, College of Charleston. 



TRICHIURUS. 



TRIGHIUKUS LEPTUETJS F S S I L I S . 

 Plate XXV. Fig. 2. 



Teeth of a ribbon fish, not differing in form nor size from the large anterior teeth of the 

 upper jaws of the existing Trichiurus lepturus, have been discovered by Prof. Holmes in 

 the Post-Pleiocene formation at Simmons'. 



Two of the specimens represented in figure 2 of plate XXV, exhibit the remarkable 



