Invertebrate respiratory system

The trachea (: tracheae or tracheas), also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all land vertebrate animals' lungs. The trachea extends from the larynx and branches into the two primary bronchi. At the top of the trachea, the cricoid cartilage attaches it to the larynx. The trachea is formed by a number of horseshoe-shaped rings, joined together vertically by overlying ligaments, and by the trachealis muscle at their ends. The epiglottis closes the opening to the larynx duri

type of lung commonly found in arachnids

anatomical structure which is part of the body of some aquatic molluscs

respiratory organ or gill which is found in many mollusks

thumb|Arion vulgaris opening its pneumostome thumb| An individual Arion rufus with the pneumostome wide open thumb|Drawing showing the different external anatomical features of a slug thumb|right|Open and closed pneumostome thumb|The pneumostome of Triboniophorus graeffei is on its dorsal surface. The pneumostome or breathing pore is a respiratory opening of the external body anatomy of a pulmonate land slug or land snail. It is a part of the respiratory system of gastropods.