On the Meaning of "Afternoon"

 In the Visnu Purana we have the pitrs partaking of the nectar of the moon in the "afternoon," when the moon consisting of just two digits, is said to be reduced to a fifteenth part of its original form. This can only be at the level of either the primary or the secondary bronchi. So it must be these generations of the bronchial tree that are designated as the "afternoon." This also makes perfect sense in the light of the statement that it is always mid-day over Mt Meru.