<P> The ink sac is a muscular bag which originated as an extension of the hind gut ; it is a modified hypobranchial gland . It lies beneath the gut and opens into the anus , into which its contents -- almost pure melanin -- can be squirted ; its proximity to the base of the funnel means that the ink can be distributed by ejected water as the cephalopod uses its jet propulsion . The ejected cloud of melanin is bound by mucus particles , so it forms a lump approximately the size and shape of the cephalopod , fixing the predator 's attention while the mollusc itself makes a hasty escape . </P>
<P> The ink sac is a muscular bag which originated as an extension of the hind gut ; it is a modified hypobranchial gland . It lies beneath the gut and opens into the anus , into which its contents -- almost pure melanin -- can be squirted ; its proximity to the base of the funnel means that the ink can be distributed by ejected water as the cephalopod uses its jet propulsion . The ejected cloud of melanin is bound by mucus particles , so it forms a lump approximately the size and shape of the cephalopod , fixing the predator 's attention while the mollusc itself makes a hasty escape . </P>
where does the ink sac of a squid empty into
where does the ink sac of a squid empty into
into the anus
into the anus