may i ask a question about Astrologia Gallica book 23

1
when reading astrologia gallica book 23 and as an example the revolution of father charles de condren, i realise that Morin use intercepted house?
To take an example, in page 53 he mentioned mercury joint ruler of the 9th house (radix) because virgo is intercepted in that house. Does it mean that mercury still need to be considered if a house is intercepted in natal and or revolution?.

and additionally can someone explain me the meaning of antiscion and its relation in terms of astrology

merci