Question

Spermathecal pores of Pheretima are present in …………….. segments.
A. $5/6, 6/7, 7/8{\rm{ and }}8/9$
B. $6/7, 7/8, 8/9{\rm{ and }}9/10$
C. $1/2, 2/3, 3/4{\rm{ and }}4/5$
D. $14/15, 15/16, 16/17{\rm{ and }}17/18$

Answer 1

Hint: Pheretima is the generic name for earthworms and the whole body of an earthworm is made up of about 100-150 segments. An earthworm is a hermaphrodite animal i.e., both male and female sex organs are present within the same animal. Four pairs of spermathecal pores are present in earthworm through which spermatheca (receives and stores sperms during the copulation process) opens.

Complete answer:
-Option (A) is correct. In earthworms, spermatheca is an organ of the female reproductive tract and it is an internal sac that is pear-shaped. The main function of spermatheca is to receive and store the sperm from the male component of the body during copulation. Four pairs of spermatheca lie in the segments $5/6, 6/7, 7/8$ and $8/9$. The spermatheca opens to the exterior through four pairs of spermathecal pores that lie ventrolateral in the grooves between $5/6, 6/7, 7/8{\rm{ and}}8/9$ segments.
-Option (B) is incorrect. The spermathecal pores lie ventrolateral in the grooves from ${5^{th}}$ to ${9^{th}}$ segments and not from ${6^{th}}$ to ${10^{th}}$ segments.
-Option (C) is incorrect. The nerve cord is present in the ${3^{rd}}$ and ${4^{th}}$ segments of the earthworm. The alimentary canal starts from the first segment and ends at the last segment. The blood glands are present in segments ${4^{th}}$,${5^{th}}$, and ${6^{th}}$.
-Option (D) is incorrect. The female genital pore is located in the${14^{th}}$ segment and the male genital pore is located in the ${18^{th}}$ segment. The clitellum, thickened and non-segmented section of the body wall is located in 14, 15, and 16 segments.

Hence, the correct option is (A).

Note: Earthworms possess segmented body structure and the spermathecal pores through which spermatheca opens to the exterior are present in between the grooves of $5/6, 6/7, 7/8{\rm{ and }}8/9$ segments, ventrolateral.