Re: DUMB METATHERIANS vs EVIL, SMART PLACENTALS

[ELurio@aol.com]

In a message dated 5/17/01 3:26:52 PM, twilliams_alpha@hotmail.com writes:

<< In some marsupials (including kangaroos) a "spare" embryo is available in 
the uterus, and is held for several months in a sort of stasis (called 
diapause).  This embryo (a blastocyst - a ball of 70-100 cells) is "ready to 
roll" if the first litter dies prematurely - or if the litter survives and 
has left the pouch. >>

Some of these embryos, or so I've read, are incased in eggshells. True 
ovivipory.

eric l.