Describe the external features of a leech with a labelled diagram.
How to lay out the answer. Follow the frame, then write it in your own words.
1 · Open in one line. Hirudinaria granulosa, the Indian cattle leech, is a sanguivorous freshwater annelid.
2 · Body shape and colour. Long, soft and segmented; dorsally convex, ventrally flat; olive green above, orange-red below.
3 · Segments and regions. 33 segments with annuli; six regions: cephalic, pre-clitellar, clitellar, middle, caudal and posterior sucker.
4 · Draw and label. [Ventral view: anterior sucker, mouth, clitellum, male and female genital pores, nephridiopores, posterior sucker. Dorsal view: eyes, anus]
5 · Openings. Mouth in the anterior sucker; anus on the dorsal side of the 26th segment; male pore on the 10th, female pore on the 11th; 17 pairs of nephridiopores.
6 · Real life. Leeches cling to the legs of farm workers in wet paddy fields with their suckers.
7 · Close in one line. Its suckers and soft, segmented body suit its blood-sucking life.
Scoring tip: Learn the segment numbers in the regions table; one-mark questions often ask for them.
