Question

C.Describe the external anatomy of two of the three following invertebrates.gestode acanthocephalam, earthworm. (6 points)

Answer 1

Cestoda - contairs flat segmented body, narrow at anterior and broad at posterior region. - Body contains following parts : * O Head / scolex - Pointed at terminal region known as Rostellum connected with 4 suckers. - Just below Rostellum at contains a series of chitinous hooks for attachment. Neck A small segment situated a linked head having continuous budding for the formation - of segments . Shobilla | Proglohids contains 800 - 1000 segments having following parts Ô Anterior immature segments which contains only male gonads ② middle mature segmente contain male & female gonads born Gravids are last 100 to 150 segements contain mature eggs & continious remoral of terminal segment facrown as Apolysis

Cestode # Rostellum Hooks salg al Head /scolex Suckers Neck Immature - segment's (Phool. Hra- mature (Proglottide) - Strobilla HI

Earth worm - Body of Earthroom has 100-200" segments - First segment Peristomium. - A dorsal fleshy love like structure overhanging the mouth like a hood called prostomium - Prostomium bears digging burrows - Internal segmental groove found between every a segments In each of the 4 inter segmental grooves between segment 5/6, 6/7, 7/8 and 8/9 there is a pair of ventro - atral elliptical spermathecal pores 14-15-16 segments have a th pink coloured layer around them. This thick collor or girdle like thickening known as "cin gulum" or clitellum, made up of glandular cells. - First segment of citellum or 14th segment has femall gonopore" or female genital pore is located at mid ventral of this 14th segment - 18th segment - rentro lateral al pais male Поро е - 17 and 19 segments - Pair of genetalia on ventro lateral position - They help in hinding 2 Earthworm in ventro lateral condition at time of coapulation

Prostomium -mouth Ji Penistomium Setal metamers & P ºp sperma thecal pore e 14 - female genital pore - Clitellum 16 > 1. Genital papillal 118 779 - Male genital pores 521 T22