Origin of tail fan
Examples from the Web for tail fan
The uropods no longer form a tail-fan, but are adapted for firmly wedging the hind part of the body into the coils of the shell.
The uropods are generally very small, and do not form a tail-fan.
T, telson, having the uropods or appendages of the last abdominal somite spread out on either side of it, forming the “tail-fan.”