Decades (literally) ago when I began trying to figure out what this organized protein was in type Ii cells, I received some peripheral canine lung tissue from from a researcher whose name I actually don’t remember.  Several blocks were processed as for routine transmission electron microscopy and occasionally a type II cell would show cisternae of RER which had a protein that was organized in layers similarly to the intracisternal bodies in ferret and guinea pig.  Picture is below.  Intracisternal space with paracrystalline protein organized parallel to the long axis of the RER membrane, cyan; funny organization of something (too small to be ribosomes) at the end on the left, green; lamellar bodies, gold; ribosomes, purple. No nuclear or mitochondrial  profiles are in this cropped image of a type II alveolar cell.