Internal shell structures. Internal views of the shells of A, Congeria jalzici sp. nov., B, Congeria kusceri, C, Congeria mulaomerovici sp. nov., and D, the ecophenotype of Congeria jalzici sp. nov. from the Lukina Jama-Trojama Cave System. Aı, Bı, Cı, and Dı are details of the hinge plates of the four specimens with the arrows pointing to the septa on which is inserted the anterior adductor muscles. Abbreviations: AA - Anterior adductor muscle scar; ABR - Anterior retractor muscle scar; BN - Byssal notch; JS - Juvenile shell; L - Ligament; PA - Posterior adductor muscle scar; PBR - Posterior byssal retractor muscle scar; PL - Pallial line; R - Resilifer; U - Umbo.