The most conspicuous organ, the crescent-shaped gonad, is gray or green in females and cream colored in males. It extends around the side opposite the pores and to the rear of the abalone. The abalone has a pair of eyes, a mouth and an enlarged pair of tentacles. Inside the mouth is a long, file-like tongue called the radula, which scrapes algal matter to a size that can be ingested. The gill chamber is next to the mouth and under the respiratory pores.
Water is drawn in under the edge of the shell, and then flows over the gills and out the pores.
Waste and reproductive products are carried out in the flow of water. Since it has no obvious brain structure, the abalone is considered to be a primitive animal. However, it does have a heart on its left side and blood flows through the arteries, sinuses and veins, assisted by the surrounding tissues and muscles. Click on the link to read some information about Red Abalone. The sexes are separate and can be distinguished in individuals as small as one inch when the gonads begin to develop.