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Re: Dino heart--Williston's prediction comes true!

The news of a fossil dinosaur heart brings to mind this 
passage from Samuel W. Williston's 1914 classic book Water 
Reptiles of the Past and Present, in the chapter on 
crocodilia (pg. 199).

..[T]he crocodiles differ from all other living reptiles 
in having a four-chambered heart, like that of birds and 
mammals, that is, a heart with two auricles and two 
ventricles. This more perfect structure of the circulatory 
organs does not, however, insure, at all times a complete 
separation of the pure or arterial blood from the impure 
or venous blood, since the blood may be more or less 
intermixed outside of the heart by a connection between 
the venous and arterial systems. Whether these imperfectly 
developed organs, so suggestive of a higher and more 
perfect mode of respiration, are the vestiges of what were 
once among some reptiles functional structures, or whether 
they are rudiments of a higher organization, developing 
independently in these creatures, cannot be positively 
determined, but it seems very probable that, far back in 
geological times, some reptiles, especially the 
pterodactyls and dinosaurs, had their respiratory and 
circulatory systems more like those of the birds and 
mammals of today. Unfortunately, however, if such was the 
case, we may never be able to prove it, although proof 
would not be impossible; stranger things than fossil 
hearts have been found by paleontologists!