Hijo lejitimo digo de padres no conosido

I have commonly seen the term "hijo de padres no conosidos" which I understand.

I occasionally see the term "hijo lejitimo digo de padres no connsidos." What does this mean? If the child is legitimate, why are the parents' names not given?

The records I am researching are baptisms of Indians in the 1800-1815 period. "Padres no conosidos" is very common, perhaps more than a third of the baptisms.

George Fulton
Pleasanton, CA