Nova Acta Academice J^atiirtB Curiosorum. 487 



appendix. The Calymenef cequalis is from the same locality: it most 

 nearly resembles the Calymene concinna, Dalm., and, like it, approaches 

 very closely to the genus ^saphus. It is figured in the accompanying 

 plate. 



The second section of the memoir is devoted to an essay " On the 

 Mastodon Arvernensis of Eppelsheim." Of this species, which was 

 unknown to Cuvier, and first described by MM. Croizet and Jobert, 

 portions, consisting of the left half of the upper jaw and some isolated 

 molar teeth, exist in the Museum of the Grand Duke of Hesse Darm- 

 stadt. They were found at Eppelsheim, near Alzei, in the Grand 

 Duchy; and are more worthy of notice as they fill up some deficiencies 

 in the account of the skeleton which the first describers were compelled, 

 from the incompleteness of their materials, to leave open to subsequent 

 investigation. The whole of the materials are described at length, and 

 the differences existing between them and the corresponding parts of 

 Mast, niaximus and angustidens are carefully noted. It appears that, 

 in addition to the Auvergnian and Hessian habitats, the species is found 

 in the Jura formation at Sal mandingen and on the Heuberg; and also 

 at Friedrichsgemijnd in Bavaria. In the last named locality it occurs in 

 a heliciferous limestone in company with remains of Mastodon angus- 

 tidens, Palceothcrium Aurelianense, Rhinoceros incisivus, Chceropoia- 

 mus Scemmeringii, a Lophiodon, a small carnivorous animal, a Cervus, 

 Tortoises, and other terrestrial quadrupeds ; with regard to which, and 

 to the tertiary formation in which tbey are found. Dr. Meyer states that 

 he is preparing a separate memoir. The plate represents the Eppelsheim 

 fragment of the upper jaw. 



" The genus ^ptychus," Mey., (which is synonymous with Trigonel- 

 lites. Park., Telliniles, Schloth., Icthyosiagones, Bourd., and Lepaditcs, 

 Germ.,) is the subject of the following section. These paradoxical fossils, 

 although known and figured so early as the time of Scheuchzer, and 

 examined and described by many subsequent oryctologists, have hitherto, 

 according to our authour, been completely misapprehended, as regards 

 their affinities and classification. To the hypothesis that they are the 

 remains of bivalve shells, which at first sight they closely resemble, lie 



