Just had a bit of a spook from my Brother. Ate some piel de sapo melon seeds and he said they are toxic. Are they? Should I be worried?  
I can find no evidence via internet search that the seeds of Piel de Sapo melons have any toxicity whatsoever.  Even if they did, eating a handful of seeds would be harmless.  For example, while apple seeds are definitely toxic, you have to eat several dozen of them to feel any ill effects. 