1) Homologue 
• (n.) That which has the same fundamental type of structure with something else; thus, the right arm is the homotype of the right leg; one arm is the homotype of the other, etc.
(ho´mo-tīp″) a part having reversed symmetry with its mate, as the hand. adj., homotyp´ic., adj.
A homotype is a specimen not used in the literature but identified by a specialist, after analysis and comparison with the attributes of a holotype.
Hom'o·type noun [ Homo- + - type .] (Biol.) That which has the same fundamental type of structure with something else; thus, the right arm is the homotype of the right leg; one arm is the homotype of the other, etc. Owen. 
Type: Term Pronunciation: hō′mō-tīp Definitions: 1. Any part or organ of the same structure or function as another, especially as one on the opposite side of the body.
an organ or part having a structure similar to that of another organ or part; homologue.