Trachea Diffusion of oxygen and carbon dioxide takes place across the walls of the smallest tubes, called tracheoles, which penetrate tissues and even indent individual cells. Gas may be conducted through the respiratory system by means of active ventilation or passive diffusion. Unlike vertebrates, insects do not generally carry oxygen in their haemolymph. This is one of the factors that may limit their size. A tracheal tube may contain ridge-like circumferential rings of taenidia in various geometries such as loops or helices. Taenidia provide strength and flexibility to the trachea. In the head, thorax, or abdomen, tracheae may also be connected
Spelling of Shakespeare's name centre is most commonly used, and why it is sometimes hyphenated. Kathman argues that any name that could be divided into two clear parts was liable to be hyphenated, especially if the parts could be interpreted as distinct words. Later editions of Shakespeare's works adopted differing spellings, in accordance with fashions of modernised spelling of the day, or, later, of attempts to adopt what was believed to be the most historically accurate version of the name. When he was referred to in foreign languages, he acquired even more variant spellings. 18th-century French critics were known to use "Shakpear, Shakespehar, Shakespeart,