Question

Hectocotylus arm of Sepia is
(A) Right third
(B) Left third
(C) Right fourth
(D) Left fourth

Answer 1

Hint: Sepia is also known as Cuttlefish. It has a total of eight arms and two additional elongated tentacles and it’s the centermost arm or the arm which is present in the middle is known to be a hectocotylus.

Complete answer:
Hectocotylus arm of Sepia is Left fourth. A hectocotylus is one of the arms of male cephalopods that are specialized to store and transfer spermatophores to the female. Structurally, hectocotylus is muscular hydrostats. depending on the type of species, the male may use it as a conduit to the female, or he may wrench it off and present it to the female.
So, the correct answer is ‘Left fourth’.

Additional Information: Cuttlefish or cuttles are marine molluscs which come under the order Sepiida. These cuttles belong to the category of Cephalopoda. Cephalopoda also includes other organisms like squid, octopuses, and nautiluses. Cuttlefish have a novel internal shell, the cuttlebone, which is employed for control of buoyancy. These fishes mainly eat small molluscs, crabs, shrimp, fish, octopus, worms, and other cuttlefish. Their predators are the dolphins, sharks, fish, seals, seabirds, and other cuttlefish. The common life expectancy of a cuttlefish is about 1–2 years. The family Sepiidae, which contains all cuttlefish, survives in the tropical and temperate ocean waters. They're mostly animals that live in shallow water. Although they're known to travel to depths of about 600 m (2,000 ft).

Note: The hectocotylus arm was first described in the biological works of Aristotle.
Although Aristotle knew of its use in mating, he also thinks that maybe a tentacle could deliver sperm. The name hectocotylus was devised by G.Cuvier.