BIOL 2030 Chapter Notes - Chapter 8: Molgula, Endostyle, Ciona
26 Apr 2016
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Soft bodied, unsegmented, body divided into three parts; worm-like. Three germ layers; coelom (3 parts) lined with peritoneum. Paired pharyngeal slits clefts used for respiration; no gills. Open circulatory system 1 pulsating vessel. The nervous system diffuse; dorsal + ventral nerve cords. Thoracic: pharyngeal slits + internal gonads/genital ridges (may cause lateral body bulges) Notochord, single dorsal tubular nerve cord; pharyngeal slits; post-anal tail; endostyle. Central nervous system is dorsal; notochord (cartilaginous rod) ventral to it. Tunicate larva: examine: buccal/incurrent siphon (mouth); atriopore (excurrent siphon, otocyst (otolith) balance; eyespot (diffuse pigminted, notochord in postanal tail. Well-dev. notochord in adults extending from head to tail. Amphioxus (pharyngeal section: examine: dorsal fin (+ skeletal support of fin rays), ventral metapleural forlds, notochord, myomeres (muscular blocks), myosepta (connective tissue, transverse muscles in floor of atrium, atrium cavity surrounding sides & ventral surface of pharynx. Gill bars @ oblique angle to transverse; close together.
