The James River Spinymussel, or P. Collina, is a mussel that inhabits the James River watershed. An average P.Collina measures just under three inches and is enveloped by a dark brown shell which sometimes has spines, or spikes, growing from the top of each shell. These shells are both attached to the posterior and anterior abductors inside the mussel in order to keep the shell closed. The interior anatomy of the P. Collina consists of many organs, including the liver, the stomach, the gonad, the heart, and the kidney. 
There is also a gill used to filter water for oxygen and trap food for movement to the palps, which is the tube used to move food from the gills to the mouth.  Because the mussel is always in water, the kidney filters the water and fluid toxins consumed by the mussel. Once the food and waste are broken down in the kidney and compressed in the rectum, all waste materials are disposed of through the excurrent siphon. There are true males and true females, therefore they are not hermaphrodites. The males have the ability to release sperm into the water, and the females receive the sperm through their siphons.