1. For storage and road transport the wings folded at two hinge lines . 2. The rear of the elevators at the rudder hinge line . 3. The Pentamerida, Terebratulida, Atrypida and Athyridida have narrow hinge lines . 4. The hinge line is not as short as found in the Rhynchonellida or Athyridida. 5. There is a small, partly faired sprung tailskid immediately ahead of the rudder hinge line . 6. Like the ligament, the hinge teeth are also situated along the hinge line of the shell. 7. This kind of hinge line is also found in the bivalve families Glycymerididae, Nuculidae and Nuculanidae. 8. Terebratulids are also distinguished by a very short hinge line , and the shell is punctate in microstructure. 9. The Orthida and Spiriferida have wide hinge lines where the two valves ( or shells ) articulate. 10. Bivalves by definition have two ligament situated on the hinge line at the dorsal edge of the shell.
Mobile