Later the idea was discredited, but now it is making a comeback in a limited way, as we'll see later on. Spiral galaxies have a disk and a bulge, and spiral arms in the disk. Spirals with large bulges and tightly wound, smooth featured arms are called Sa's, those with small bulges and loosely wound arms with lots of structure are called Sc's, and intermediate spirals are called Sb's. Barred spiral galaxies are like spirals, but with a bar-like central feature. They are also subdivided into SBa, SBb, and SBc types.
Elliptical galaxies are just big, ovoid blobs of stars.
Most of them are featureless. The flattest we see are the E7's. In reality, of course, ellipticals are three dimensional objects, and what we see is a projection onto the plane of the sky. In reality, they may be cigar shaped or pancake shaped or anything in between. Both the largest and the smallest galaxies are ellipticals, as well as plenty of normal sized ones.