What are the large and small magellanic clouds, and the sagittarius and canis major dwarfs?

The Small Megallanic Cloud represents the smaller irregular galaxy, while the Big Megallanic Cloud represents the big irregular galaxy. Together they make up the Megallanic Clouds.

Sagittarius Major Dwarf is an elliptical galaxy.

Canis Major Dwarf is an irregular galaxy, with a mass of about a billion solar masses.