Class 11 NEET Biology Structural Organisation in Animals

(b) : In Pheretima, next to stomach is the intestine. It is a long, wide and thin walled tube extending from 25‌th ‌ segment to the last. Second or middle part of the intestine lies between 27‌th ‌ segment upto 23-25 segments in front of anus. This is characterised by the presence of a highly glandular and vascular longitudinal ridge, arising as a median in-growth of the dorsal aspect of the intestinal cavity. This is called the typhlosole. The typhlosole greatly increases the effective absorption area of the digested food in the intestine.