Nitrogenous bases are Adenine, Thymine, Uracil and Cytosine.

Nucleoside are Cytidine and Guanosine.

Explanation: There are two types of nitrogenous bases: Purines (Adenine and Guanine) and Pyrimidines (Cytosine, Uracil and Thymine).

A nitrogenous base when linked to a pentose sugar through a N-glycosidic linkage forms a nucleoside like adenosine, guanosine, cytidine and uridine.