FOSSIL SQUALID^ OF THE UNITED STATES. 195 



These teeth are often found precisely similar except in being crenated and smooth, 

 the former most likely belonging to the upper and the latter to the lower jaw. 



Agassiz describes specimens from the chalk of Malta, and from the Siviss molasse ; 

 all mine are from the Eocene of South Carolina. 



S. LATA, Agassiz. Figs. 91, 92, 93. — Distinguished by an enlarged and 

 pyramidal form, as well as by the well marked though fine dentelures over the whole 

 contour of the edges; anterior edge somewhat rounded, posterior notched, outer face 

 flat, inner swollen. The enamel extends low down on the root, which is very thick. 

 The locality of Agassiz's specimens was unknown. Mine are from the Eocene of 

 South Carolina. 



S. DENTicuLATA, Agassiz. Fig. 94. — Professor Agassiz is in doubt whether this 

 species differs from S. prisca. The perpendicular form and acute isosceles-triangular 

 form, and regular distinct and symmetrical denticulations induce me to think it a 

 separate species. I have, however, seen but a single specimen, the one figured. 



Genus NOTIDANUS, Cuvier. 



" In the genus Nottdanus, the teeth are not only of different forms in the upper 

 and lower jaws, but also vary considerably in this respect, at the anterior and 

 posterior regions of the same jaw. In the upper jaw, the anterior teeth are larcre, 

 compressed triangular plates, with the pointed apex arched backwards, and the 

 margins slightly dentated, except in the two anterior ones. The posterior teeth are 

 in the form of simple obtuse furrowed tubercles. In the lower jaw, the large anterior 

 teeth have the apex less produced; the anterior margin is finely , serrate, and the 

 posterior divided into three or more denticles. The posterior minute teeth resemble 

 those in the upper jaw. Of the larger teeth there are rarely more than four in each 

 vertical row." — Owen.* 



N. PRiMiGENius, Agassiz. Fig. 95. — I have given a figure of the only perfect 

 specimen I have met with, and think it belonged to the lower jaw. It was kindly 

 presented to me by Professor J. Wyman, of Boston, who procured it from the Eocene 

 of Richmond, Virginia. I have fragments from other localities. The crown 

 consists of a series of sharp oblique cones, of which the first is the largest and least 

 oblique, the others gradually diminishing in size towards the posterior edge. The 

 large cone is strongly indented on its lower outer half. The length of the tooth 

 greatly exceeds its height ; the inner and outer faces are both prominent and differ 



* Besides those of Agassiz, good figures are given of various forms of Notidaniis in the old work of Scilla, 

 De corporibus marinis, Romse, 1747, and in the recent elaborate work of C. L. Bonaparte, Iconographia della Fauna 

 Italica, Romae, 1832—1841. I find also others in Orydographie de Bruxdles, by F. X. Burtin; Bruxelles, 1784. 



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