Astronesthes richardsoni chin is ribbon-like and lacks a bulb or swelling at its tip. The dorsal fin has 12 to 14 soft rays and the anal fin has 13 to 18. The origin of the dorsal fin is behind the insertion of the pelvic fins. There is a dorsal adipose fin anterior to the caudal peduncle, and a small ventral adipose fin just anterior to the anus. There are two rows of photophores (luminous spots) on each side of the underside of the fish, numerous other photophores on the head and body and a luminous patch on the edge of the preoperculum;
Caudal cell mass The cavities formed from the initial and secondary neuralation combine to form one uninterrupted cavity. There is still specualtion on the formation of the caudall cell mass in humans with arguments being made for it arising from many cavities or the continuing growth of the neurocele from the initial neuralation. The caudal cell mass will ultimately differentiate and form into many sacral structures such various nerve endings and the conus medullaris. The caudal cell mass plays a role in many diseases and abnomalities related to the spinal cord. One group of abnormalities it plays a role in are occult spinal