Question

Harderian glands are absent in.
A. Rabbits
B. Men
C. Crows
D. None of the above

Answer 1

Hint: Harderian glands are pigmented lacrimal (tear) glands located in the eye’s orbit of tetrapods including reptiles, amphibians, birds and mammals which possess a nictitating membrane.

Complete answer:
The harderian gland is found within the eye’s orbit and they act as secretory glands. They secrete lipid and porphyrin- rich material which helps in lubricating both the eye and eyelids.

Let us look at each option one by one
- Option A: Rabbits are tetrapods and they also possess a nictitating membrane. Hence, harderian glands are present in rabbits. Thus, this answer is incorrect.
- Option B: Men/Humans possess tear glands but the nictitating membranes in the human eye have evolved out of use and become rudimentary in nature; as a result humans do not possess Harderian glands. Thus, this is the correct option.
- Option C: Crows are tetrapods which possess the nictitating membrane in their eye; resulting in the presence of the harderian gland. Therefore, this option is incorrect.
- Option D: Since humans/men do not possess the harderian glands, option (B) is the correct answer. Thus, none of the above is an incorrect option.

Therefore, the correct answer is (B) Men.

Note: The nictitating membrane is a transparent or translucent membrane that acts as the third eyelid in some animals and birds which draws across the perpendicular to the movement of the eyelid and protects the eye from onslaught of dust and snow as well as allows these organisms to have clear vision underwater.