BIOL 371 Lecture Notes - Lecture 14: Prostomium, Anterior Segment Of Eyeball, Body Fluid
Document Summary
Cuttlefish have small shells that is enclosed by mantle. Squids have a very small shell called a pen which is a long thin proteinaceous strip. Have a funnel (a fold of mantle) or siphon that ejects water out. Respiration: paired gills-water moves over gills by muscular contraction. Expansion of mantle brings water in and contraction pushes it back out. Valves to make sure water goes in one direction. Gets oxygen from the gills, and has accessory hearts at the base of the gills to help keep pressure high. Eye is similar to mammals- conversion evolution example. Head has 2 components a prostomium and a peristomium. Tail end or terminal segment also called a pygidium. Externally is marked by circular rings called annuli. Internally each segment is separated from others by a septum. Gut runs through the center of the septum as does the blood vessels and nervous system. Coelom developed by schizocoely which is a split in the mesoderm.
