They are a type of external light type. This type has light extending from the back to the head is called an extracorporeal light type, and these have extracorporeal light from the back to the head.
"To come into compliance with California law and regulation, Blue Crown Aquatic will not be selling any restricted species of the taxonomic family Cambaridae, including, but not limited to crayfish. except as otherwise permitted by the California Fish and Game Code or sold to its customers restricted species of the taxonomic family Cambaridae, such sales were in violation of California law and regulation and have now been discontinued."
They are a type of external light type. This type has light extending from the back to the head is called an extracorporeal light type, and these have extracorporeal light from the back to the head.