cogollos - Spanish lettuce hearts

[dandryden]

In Spanish "cogollos" means heart or something like that. In Spain on local menus it refers specifically to the hearts of a particular kind of lettuce. Small dense hearts about 2 inches in diameter and 4-5 inches long, pale in the center to darker green outside.
Does anybody know exactly which variety of lettuce this is?
I'd like to grow it but can't find any reference to seeds associated with cogollos on the internet. Thanks.

[Naguere]

Doing a Google I came up with lettuce hearts.... and many other 'heart' things, even to a location.
From your size parameters Romain seems to fit the bill, a Little Gem heart is, well, little, but (remember, size does not matter)

[Pata_Negra]

it's probably 'little gem' as it's most common. in that case, romaine.