266 



TRANSACTIONS OF THE 



least, some of the impressions of this species which are 

 represented on the cast referred to. 



The figure of T. Beckii (vide pi. 15, fig. 6) is added in 

 order to show how closely it is allied with the buckler 

 of the Paradoxides semriboides of Brongniart and Des- 

 marest (vide Histoire Naturel des Crust. Fossil., p. 34, 

 pi. 3, fig. 5). These authors quote as a synonyme, the 

 Entomostracites scaraboides of Wahlenberg, w-ho thus 

 characterizes his species, ^'^cacus, capite hemispherico, 

 antice rotundato; fronte subovata, antrorsura aiigustiore; 

 Cauda utrinque sinuato-tridentata.'^ The author adds, 



perfect or entire specimens are rarely found. From 

 beds of fetid aluminous ampclite." Vide pi. 15, fig. 7. 



