Whilst having a break from my work I had a flick through my copy of Burke's General Armory. Under the heading of "Shiled of Arms" it mentions that there are ten classes but only lists eight. Have I missed soemthing, or to 7 & 8 count as two each? See below:

According to the received authorities, there are ten (sic)classes of arms: -

1. ARMS OF DOMINION, those borne by Sovereigns and annexed to the territories they govern.
2. ARMS OF PRETENSION, used by Sovereigns who are not in possession of the dominions to which the arms belong, but who claim, or pretend a right to them. Thus the Kings of England from Edward III to George III quartered the arms of France.
3. ARMS OF COMMUNITY, those of bishoprics, universities, cities, and other corporate bodies.
4. ARMS OF ASSUMPTION, adopted without the grant of the Sovereign or of a King-of-Arms, and used as a proper right. For instance, if a prince or nobleman be taken prisoner in lawful war, the victor may bear the arms of the person so taken, and transmit them to his heirs.
5. ARMS OF ALLIANCE, these are adopted by families or private persons, and are joined with their own heraldic bearings to denote the alliance which they have contracted by marriage. Arms of this description are impaled, or are borne in an escutcheon of pretence by those who have married an heiresses. But the latter arrangement (that of separate escutcheon) is not allowed until the death of the father of the lady.
6. ARMS OF ADOPTION are borne by a stranger in blood, and are specially granted by the Sovereign to empower the person applying for them to obtain certain moneys or estates bequeathed on the condition of his assuming the name and arms of the testator.
7. ARMS OF CONCESSION or HONOURABLE AUGMENTATION are peculiar marks of honour granted by the Sovereign for some act deserving of royal approbation.
8. ARMS PATERNAL AND HEREDITARY are those transmitted from the first possessor to his heirs; the son being a gentleman of second coat armour; the grandson a gentlemen of blood; and the great-grandson a gentleman of ancestry.