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;
Operculum (gastropod) the shell of "Charonia tritonis" is a seal made by the Minoan civilization. Opercula of certain gastropods, especially varieties from the Red Sea, have long served as an incense material in ancient Jewish tradition, as well as Arabian cultures. The operculum of conch species "Strombus tricornis" and "Lambis truncata sebae" are most commonly used in regions near the Middle East. Opercula from these conches may be the onycha incense material which is described in the Book of Exodus. Operculum powder is also an important ingredient in Chinese and Japanese incense making. Here it is called ""bèi xiāng"" (Chinese: 貝香; "lit."