#1 Todo lo que debes saber de las orejas de los perros pero está en inglés:
http://www.whole-dog-journal.com/issues/7_10/features/Canine-Ear_15661-1.html
Y esto http://www.ehow.com/facts_5856520_slits-dog-ears_.html
Terminology
In medical terminology, the slit on a dog's ear is called the "cutaneous marginal pouch." In everyday English, this translates to "a small pouch of the skin."
Identification
The cutaneous marginal pouch is located on the outside portion of a dog's ear, farthest away from the body. It is located between the conch and scaphal of the ear.
Purpose
The slit on a dog's ear serves no known purpose, according to the book "Canine Anatomy."
Considerations
All dogs posses this slit. It may be more readily apparent on some dogs, but this is perfectly normal.
Fun Fact
Dogs have 15 muscles in their ears that enable them to turn their ear in almost every direction.
Read more: What Are the Slits on Dog Ears? | eHow.com http://www.ehow.com/facts_5856520_slits-dog-ears_.html#ixzz2RX1NU1ul
Vamos que no tiene una función conocida, seguramente un resto vestigial de algo que tendría su utilidad.