CIVILIAN PERMANENT CHANGE OF STATION (PCS) CHECKLIST. A PCS move involves a great deal of advance planning and hard work. We would like to make this transition as. smooth as possible by providing this guide. Remember that this guide is just that-a guide, and does not supersede. any laws, regulations or directives that are already in place. 6 months out Report date -180 days.
Thus it is clear that cloaca is used for excretion as well as reproduction. This is also the opening that is used for laying eggs. Anus on the other hand is simply an opening at the distal end of the alimentary canal. It is a passage for undigested waste only.
Crayfish use their gills to breathe. A crayfish has a gill at the base of each leg. These gills are very delicate and are covered by the crayfish's carapace, or shield. This carapace is aligned backwards from the head, allowing water to run through in a channel over the gills, which provides a continuous source of oxygen that allows the crayfish to breathe.