Amphioxus Tectum

Amphioxus Tectum

Frontal Eye

The Human Tectum

Midbrain tectum (Wiki) 
Brief description of human tectum with undecipherable picture.  This is said to be the site of the highest level of sensory-motor integration in animals that don't have a cortex.   

Neuroanatomy Tutorial from MIT 9.97 
Click on   'tectum of midbrain', and a red arrow will point to it. 

Another tutorial from MIT 9.97 
Scroll down to 'Midbrain' in the box in the upper left-hand corner and click on the links to see the slides. 
SC = superior colliculus 
IC = inferior colliculus 

BrainInfo-neuroanatomy (OD) 

Note:  there are eight more brain imaging links plus another subindex in
Human Neuroanatomy.