A fully executed contract date begins once both parties signed it. In your case, since you signed them first, the date begins when the seller/affixes his signature. However, the delivery of the ratified contract should also be considered. Consult your realtor and a lawyer.
A group of spiders is called a cluster or clutter. Spiders belong to the group of animals called arachnids.
All spiders have eight legs. Like insects, which have six legs, spiders belong to the phylum Arthropoda but are members of a different class, Arachnida.