This is a Vintage 1961 Schwinn Mark VI Jaguar middleweight bicycle in green.  This bike will definitely be a project.  This is the coaster brake model.

This bike is missing the original front rack, rear rack, front fender, horn, original grips, cranks, tires, headlight, and pedals.
The Jaguar has several scratches, dings and dents, with some surface rust on most items.

The front fork is also bent slightly backwards. 
You can still ride it, but the handling is a little sketchy, especially with the light breaking action on the back - would suggest a hub overhaul.
This Jaguar was built in Chicago, IL, in September of 1961.

Measurements:

Seat Tube - 18"

Top Tube - 22"

Stand-over Height - about 31"

Specifications:

Seatpost - steel, original

Saddle - seems original, still green and white, rough

Stem - original quill stem

Handlebars - about 21"

Crankset - Steel 1 piece, not original

Pedals - newer block style pedals, not original

hubs - Bendix rear coaster brake hub - needs a rebuild, schwinn front hub with surface rust
rims - steel 26" rims, showing lots of surface rust

Chain will also need some work, showing lots of rust but is flexible

Serial #J127870

Reference #84572