Genus Ninth. Ampyx.
Body very short, contractile.
Buckler large, triangular, gibbous; eyes not remarkable.
Abdomen short, articulations few (6?), trilobate.
Tail expanded, not so large as the head.
Professor Dalman has two other genera, which he calls Olenus and Battus, the first is the Paradoxides, and the second the Agnostus of Brongniart.
In the 8th Volume of Annales des Sciences Naturelles there is a highly valuable paper "Sur les Trilobites et leurs gisemens," by the Count Rasoumowsky, in which he describes some new trilobites from Russia; the one which he has figured and described as a Calymene[9] from Tzarsko-Selo, undoubtedly belongs to a new genus, very near to the Isotelus. The middle lobe is visible or naked through its whole extent, and the lateral lobes near the tail are covered with a thick cuticular membrane. This genus we propose to call Hemicrupturus, and may be thus characterized.
[9] The editors of the Annales remark that this is not a Calymene, but that it appears to belong to the genus Asaphus.
Genus Tenth. Hemicrupturus.[10]—Green.
[10] From three Greek words which signify half-concealed tail.