What is the relation between the Eight Consciousnesses and the Five Aggregates? What is the relation between the Eight Consciousnesses and the Five Aggregates?

Are all the 8 consciousnesses subtypes of the fifth aggregate (vijñāna/viññāṇa)? The name suggests so, but it looks strange to me: the first 5 of the 8 consciousnesses seem to be more related to the third aggregate (samjñā/saññā). I would be glad for a clarification.
All 8 types of consciousness described in Yogacara texts fit into the aggregate of consciousness, not perception. The confusion comes down to difficulty in the English translations for these terms. 

The word translated as perception doesn't actually mean perception in the ordinary English sense of the word. In ordinary English perception means to be aware of something through the senses, but that is not the meaning of the word saññā.  refers specifically to the way that something is interpreted by the mind, especially in terms of pattern recognition and memory. For example, when you look at a chair, you are aware of actually seeing something (which is eye-consciousness) and at the same time you are giving an interpretation to what it is, which in this case is a chair. This second layer of gathering things together and interpreting them is what saññā is in Buddhism.