1. 
   Monotremes
   are the most primitive Mammals and are egg-laying. The Duck-Billed Platypus is a famous example.
   Found op http://crazycreatures.org/glossary/
   
   
2. 
   monotremes
   Egg-laying mammals; e.g., the spiny anteater and the duck-billed platypus.
   Found op http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookglossm.html
   
   

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