James gave his life, why no protection from him?

[Eva]

No: HPFGUIDX 106590

I haven't joined in a long, long time, but I had a few thoughts. 

We know about Lily's sacrifice and the mark it left on Harry. But 
how about the shape of Harry's Patronus as a mark of James' 
protection? It has never been exactly explained why Patroni take a 
certain shape. 

The only part I don't know how to place is where the shapes of 
Hermiones and Cho's Patroni come from.  

"Eva"